Smoking as a predictor of negative outcome in lumbar spinal fusion

The effect of cannabinoids on single-level lumbar arthrodesis outcomes in a rat model

BACKGROUND CONTEXT

The opioid epidemic is a public health crisis affecting spine care and pain management. Medical marijuana is a potential non-opioid analgesic yet to be studied in the surgical setting since its effects on bone healing are not fully understood. Studies have demonstrated analgesic and potentially osteoinductive properties of cannabinoids with endocannabinoid receptor expression in bone tissue.

PURPOSE

We hypothesize that tetrahydrocannabinol (THC) and cannabidiol (CBD) will not decrease bone healing in spinal fusion.

STUDY DESIGN

Seventy-eight adult Sprague-Dawley rats were used for this study. Utilizing allogenic bone grafts (6 donor rats), posterolateral inter-transverse lumbar fusion at the L4-L5 level was performed. The animals were equally divided into four treatment groups, each receiving 0.1 ml intraperitoneal injections weekly as follows: placebo (saline), 5 mg/kg THC, 5 mg/kg CBD, and a combination of 5 mg/kg THC and 5mg/kg CBD (Combo).

METHODS

Callus tissue was harvested 2- and 8-weeks post-surgery for qPCR assessment to quantify changes in the expression of osteogenic genes. Manual palpation was done to assess the strength of the L4-L5 arthrodesis on all rats. μCT image-based callus analysis and histology were performed. One-way ANOVA followed by post hoc comparisons was performed.

RESULTS

μCT demonstrated no significant differences. Treatment groups had slightly increased bone volume and density compared to control. qPCR at two weeks indicated downregulated RANKL/OPG ratios skewing towards osteogenesis in the CBD group, with the THC and CBD+THC groups demonstrating a downward trend (p>.05). ALPL, BMP4, and SOST were significantly higher in the CBD group, with CTNNB1 and RUNX2 also showing an upregulating trend. The CBD group showed elevation in Col1A1 and MMP13. Data at eight weeks showed ALPL, RUNX2, BMP4, and SOST were downregulated for all treatment groups. In the CBD+THC group, RANK, RANKL, and OPG were downregulated. OPG downregulation reached significance for the THC and CBD+THC group compared to saline. Interestingly, the RANKL/OPG ratio showed upregulation in the CBD and CBD+THC groups. RANKL showed upregulation in the CBD group. At 2 and 8 weeks, the CBD treatment group showed superior histological progression, increasing between time points.

CONCLUSION

This study demonstrates that CBD and THC have no adverse effect on bone healing and the rate of spinal fusion in rats. Osteogenic factors were upregulated in the CBD-treated groups at two weeks, which indicates a potential for bone regeneration. In this group, compared to control, the RANKL/OPG ratio at the early healing phase demonstrates the inhibition of osteoclast differentiation, enhancing bone formation. Interestingly, it shows promoted osteoclast differentiation at the later healing phase, enhancing bone remodeling. This aligns with the physiological expectation of a lower ratio in the early phases and a higher ratio in the later remodeling phases.

CLINICAL SIGNIFICANCE

CBD and THC showed no inhibitory effects on bone healing in a spinal fusion model. Moreover, histologic and gene expression analysis demonstrated that CBD may, in fact, enhance bone healing. Further research is needed to confirm the safe usage of THC and CBD in the post-operative setting following spinal fusions.

Influence of smoking on patient-reported outcome measures (PROMs) in patients undergoing surgery for adult spinal deformity: a propensity score-matched analysis

PURPOSE

The purpose of this study was to determine the isolated influence of smoking in patient-reported outcome measures (PROMs) for adult spinal deformity (ASD) surgery excluding known tobacco-related complications.

METHODS

Retrospective analysis of a prospective multicenter ASD database. Patients operated on ASD with 2 year post-operative follow-up were included. Former smokers (non-active smokers) and patients developing mechanical or infectious complications were excluded. Changes of PROMs over time were analyzed using mixed models for repeated measures (MMRM). Propensity score matching (PSM) (1:1 ratio, caliper 0.10) was performed without replacement using optimum algorithm, tolerance ≤ 0.001, and estimated with 95% confidence interval (CI). PROMS in both groups were compared by paired t test or Wilcoxon signed-rank test.

RESULTS

692 out of 1246 surgical patients met our inclusion criteria. 153 smokers were matched with 153 non-smokers according to age, BMI, number of fused levels, and global tilt. After PSM both groups were homogeneous regarding baseline parameters, surgical data, and complications (mechanical complications and infection excluded). Smokers had worse baseline results for SRS-total, SRS-pain COMI-back, and ODI; smokers also showed worse 2-year outcomes for SRS-total, SRS-function, SRS-pain, SRS-self-image, and ODI. However, no differences between the two groups were found in the improvement from baseline to 2-year follow-up or in the timing of this improvement (MMRM). The proportion of patients reaching the minimal clinically important difference (MCID) after surgery was similar in the two groups, but the proportion of patients reaching patient acceptable symptom state (PASS) was significantly lower in smokers for SRS-Subtotal, SRS-function, and SRS-image.

CONCLUSION

Even in the absence of smoking-related complications, smokers had worse PROMs at baseline and 2 years after surgery with less patients achieving PASS, but similar degrees on improvement compared to non-smokers. The proportion achieving MCID was also similar between the two cohorts.

Preoperative fatty infiltration of paraspinal muscles assessed by MRI is associated with less improvement of leg pain 2 years after surgery for lumbar spinal stenosis

PURPOSE

Fatty infiltration (FI) of the paraspinal muscles may associate with pain and surgical complications in patients with lumbar spinal stenosis (LSS). We evaluated the prognostic influence of MRI-assessed paraspinal muscles' FI on pain or disability 2 years after surgery for LSS.

METHODS

A muscle fat index (MFI) was calculated (by dividing signal intensity of psoas to multifidus and erector spinae) on preoperative axial T2-weighted MRI of patients with LSS. Pain and disability 2 years after surgery were assessed using the Oswestry disability index, the Zurich claudication questionnaire and numeric rating scales for leg and back pain. Multivariate linear and logistic regression analyses (adjusted for preoperative outcome scores, age, body mass index, sex, smoking status, grade of spinal stenosis, disc degeneration and facet joint osteoarthritis) were used to assess the associations between MFI and patient-reported clinical outcomes. In the logistic regression models, odds ratios (OR) and 95% confidence intervals (CI) were calculated for associations between the MFI and ≥ 30% improvement of the outcomes (dichotomised into yes/no).

RESULTS

A total of 243 patients were evaluated (mean age 66.6 ± 8.5 years), 49% females (119). Preoperative MFI and postoperative leg pain were significantly associated, both with leg pain as continuous (coefficient - 3.20, 95% CI - 5.61, - 0.80) and dichotomised (OR 1.51, 95% CI 1.17, 1.95) scores. Associations between the MFI and the other outcome measures were not statistically significant.

CONCLUSION

Preoperative FI of the paraspinal muscles on MRI showed statistically significant association with postoperative NRS leg pain but not with ODI or ZCQ.

Impact of obesity on adult spinal deformity (ASD) long-segment spinal fusion radiographic and clinical outcomes

STUDY DESIGN

Retrospective chart review of patients receiving long-segment fusion during a five-year period.

OBJECTIVE

To determine whether obese patients receive comparable benefits when receiving long-segment fusion compared to non-obese patients and to identify factors that may predict hardware failure and post-surgical complications among obese patients.

METHODS

Demographic, spinopelvic radiographic, patient-reported outcome measures (PROMs), and complications data was retrospectively collected from 120 patients who underwent long-segment fusion during a five-year period at one tertiary care medical center. Radiographic measurements were pelvic incidence, pelvic tilt (PT), lumbar lordosis, L4-S1 lordosis, thoracic kyphosis, sagittal vertical axis, PI-LL mismatch, and proximal junction cobb angle at upper instrumented vertebrae + 2 (UIV+2). PROMs were Oswestry disability index, numeric rating scale (NRS) Back Pain, NRS Leg Pain, RAND SF-36 pain, and RAND SF-36 physical functioning. Included patients were adults and had at least 2-years of postoperative follow-up. Descriptive and multivariate statistical analysis was performed with α = 0.05.

RESULTS

Patients with a BMI ≥ 30 (n=63) and patients with a BMI < 30 (n=57) demonstrated comparable improvements (P>0.05) for all spinopelvic radiographic measurements and PROMs. Each cohort demonstrated significant improvements from pre-assessment to post-assessment on nearly all spinopelvic radiographic measurements and PROMs (P<0.05), except PT and L4-S1 lordosis where neither group improved (p=0.95 and 0.58 for PT and P=0.23 and 0.11 for L4-S1 lordosis fornon-obese and obese cohorts respectively) and SF-36 physical functioning where the non-obese cohort not statistically improve (P=0.08). Patients with a BMI ≥ 30 demonstrated an increased incidence of cardiovascular complications (P=0.0293), acute kidney injury (P=0.0241), rod fractures (P=0.0293), and reoperations (P=0.0241) when compared to patients with a BMI < 30.

CONCLUSION

This study adds to a growing body of evidence linking demographic factors with risks of hardware failure. Further, this data challenges the assumption that obese patients may not receive sufficient benefit to be long-segment surgical candidates. However, given their elevated risk for post-operative and delayed hardware complications, obese patients should be appropriately counseling before undergoing surgery.

Risk factors for nonunion in oblique lateral interbody fusion

BACKGROUND

Compared with posterior interbody fusion techniques, oblique lateral interbody fusion (OLIF) offers a larger fusion bed with greater intervertebral space access, use of larger cages, more sufficient discectomy, and better end-plate preparation. However, the fusion rate of OLIF is similar to that of other interbody fusions. This study aimed to examine the factors associated with nonunion in OLIF.

METHODS

This study examined 201 disc levels from 124 consecutive patients who underwent OLIF for lumbar degenerative diseases with 1-year regular follow-up. Demographic and surgical factors were reviewed from the medical records. Radiological factors measured were sagittal parameters, intervertebral disc angle (DA) before surgery and at the final follow-up, presence of vertebral end-plate lesions, and cage subsidence. Multivariable logistic regression analysis was performed to identify the factors associated with nonunion.

RESULTS

Among the 201 discs, 185 (92.0%) achieved union at 1-year followed up. Smoking, surgery at the L5-S1 level, not performing laminectomy, and a large intervertebral DA were factors associated with nonunion in OLIF (all P < 0.05). Multivariable logistic regression analysis showed two independent variables (surgery at L5-S1 level and not performing laminectomy) as risk factors for nonunion in OLIF.

CONCLUSIONS

Not performing laminectomy and surgery at the L5-S1 level were risk factors for nonunion in OLIF. To reduce the nonunion rate, surgeons should consider additional stabilization strategies for the L5-S1 OLIF and perform laminectomy.

Postoperative scaphoid alignment, smoking, and avascular necrosis mostly influence union rate after scaphoid reconstruction: Results from a retrospective single center study involving 370 patients

Current literature does not definitely demonstrate the superiority of any particular scaphoid reconstruction method. The primary goal of this retrospective single center study was to evaluate the influence of reconstruction techniques and other factors on the union rate after reconstruction of scaphoid nonunions. In the study, 370 patients with nonunions classified as stable (Mayo 1) or unstable (Mayo 2) depending on carpal alignment were included. Minimal radiological follow-up was 3 months. Bone healing after scaphoid reconstruction was evaluated using computer tomography scans in 294 and radiograms in 76 patients. Univariate and multivariate logistic regressions were applied in the analysis. Eight statistically significant factors that influenced the union rate were fixation method, type of previous operations, number of all operations, number of reconstructions, smoking, postoperative pathological lateral intrascaphoid angle (LISA>45°), avascular necrosis (AVN), and stability of nonunion. Smoking and postoperative LISA>45° significantly reduced the probability of bone fusion by approximately 4.4 and 9.5 times, respectively. Patients with reduced vascularity in the nonunion site had a 5.2 times lower chance of bone fusion. Our multivariate logistic regression model can explain 32% of failures after scaphoid reconstruction, including postoperative LISA>45°, patients' present record of smoking, and reduced vascularity in the nonunion site. However, bone graft type does not impact the union rate in general; however, in case of AVN, the tendency toward higher union rates was observed for medial femoral condyle free flaps when compared to other types of graft (non-vascularized and pedicled bone grafts considered as one group, p = 0.09).

Titanium-coated PEEK Versus Uncoated PEEK Cages in Lumbar Interbody Fusion: A Systematic Review and Meta-analysis of Randomized Controlled Trial

STUDY DESIGN

Systematic review and meta-analysis.

OBJECTIVE

This study was performed to compare the fusion and subsidence rate of titanium-coated polyetheretherketone (Ti-PEEK) versus polyetheretherketone (PEEK) cages after lumbar fusion and to investigate the clinical effect on patient-reported outcomes (PROMs).

SUMMARY OF BACKGROUND DATA

Ti-PEEK cages have been developed to combine the advantages of both titanium alloy and PEEK, but whether they are superior to uncoated PEEK cages in bone fusion is still inconclusive.

METHODS

PubMed, EMBASE, ISI Web of Science, CENTRAL, and CNKI were searched to identify randomized controlled trials that compared the efficacy of Ti-PEEK and PEEK cages in lumbar fusion. Difference in fusion rate and subsidence rate was indicated by risk ratio and its associated 95% confidence interval (95% confidence interval). Mean difference was calculated for Oswestry Disability Index and visual analogue scale for low back pain. Subgroup analysis was performed by time course after the surgery. The Grading of Recommendations, Assessment, Development and Evaluation approach was used to evaluate the certainty of evidence.

RESULTS

Four randomized controlled trials involving 325 patients (160 patients in Ti-PEEK group and 165 patients in PEEK group) that underwent lumbar fusion were included by our current study. Low to moderate evidence suggested that Ti-PEEK and PEEK cages exhibited equivalent fusion rate and subsidence rate at any follow-up time. Low to moderate evidence suggested that there was no difference in PROMs except for visual analogue scale measured at 6 months (mean difference: -0.57, 95% confidence interval -0.94, -0.21; P =0.002) but the difference was not clinically relevant according to the minimal clinically important difference.

CONCLUSION

Low to moderate evidence showed that Ti-PEEK and PEEK had equivalent effect in bone fusion and cages subsidence at any follow-up time after lumbar fusion surgeries. Low to moderate evidence showed no clinically important difference in PROMs.

Does Tobacco Smoking Affect the Postoperative Outcome of MIS Lumbar Decompression Surgery?

BACKGROUND

Tobacco smoking is a major cause of morbidity and mortality worldwide. Several authors reported a significant negative impact of smoking on the outcome of spinal surgeries. However, comparative studies on the effect of smoking on the outcome of minimally invasive (MIS) spinal decompression are rare with conflicting results. In this study, we aimed to evaluate clinical outcomes and postoperative complications following MIS decompression in current and former smoking patients compared to those of non-smoking patients.

METHODS

We used our prospectively collected database to retrospectively analyse the records of 188 consecutive patients treated with MIS lumbar decompression at our institution between November 2013 and July 2017. Patients were divided into groups of smokers (S), previous smokers (PS) and non-smokers (N). The S group and the PS group comprised 31 and 40 patients, respectively. The N group included 117 patients. The outcome measures included perioperative complications, revision surgery and length of stay. Patient-reported outcome measures included a visual analogue scale (VAS) for back pain and leg pain, as well as the Oswestry disability index (ODI) for evaluating functional outcomes.

RESULTS

Demographic variables, comorbidity and other preoperative variables were comparable between the three groups. A comparison of perioperative complications and revision surgery rates showed no significant difference between the groups. All groups showed significant improvement in their ODI and VAS scores at 12 and 24 months following surgery. As shown by a multivariate analysis, current smokers had lower chances of improvement, exceeding the minimal clinical important difference (MCID) in ODI and VAS for leg pain at 12 months but not 24 months postoperatively.

CONCLUSIONS

Our findings show that except for a possible delay in improvement in leg pain and disability, tobacco smoking has no substantial adverse impact on complications and revision rates following MIS spinal decompressions.

The Impact of Smoking on Delayed Osseous Union After Arthrodesis Procedures in the Hand and Wrist

PURPOSE

The purpose of this study was to evaluate the relationship between smoking and delayed radiographic union after hand and wrist arthrodesis procedures. We hypothesized that smoking would be associated with a higher rate of delayed union.

METHODS

All cases of hand or wrist arthrodesis procedures in patients aged ≥18 years from 2006 to 2020 were identified. Cases were included if they had >90 days of radiographic follow-up or evidence of union before 90 days. Baseline demographics were recorded for each case including smoking status at the time of surgery. Complications were recorded and all postoperative radiographs were reviewed to assess for evidence of delayed union (defined as lack of osseous union by 90 days after surgery). We compared active smokers and nonsmokers and performed a logistic regression analysis to estimate the odds of experiencing a delayed radiographic union.

RESULTS

A total of 309 arthrodesis cases were included and 24% were active smokers. Overall, radiographic evidence of a delayed union was found in 17% of cases. Smokers were significantly more likely to have a delayed union compared with nonsmokers (27% vs 14%). Results of the adjusted logistic regression analysis demonstrated that there was a significantly increased odds of experiencing a delayed union for patients who were active smokers compared with nonsmokers (odds ratio, 2.20; 95% confidence interval, 1.09-4.43). In addition, the rate of symptomatic nonunion requiring reoperation was higher in smokers (15%) compared with nonsmokers (6%).

CONCLUSIONS

Smoking was associated with increased odds of delayed radiographic union in patients undergoing hand and wrist arthrodesis procedures. Patients should be counseled appropriately on the risks of smoking on bone healing and encouraged to abstain from nicotine use in the perioperative period.

TYPE OF STUDY/LEVEL OF EVIDENCE

Prognostic II.

The Risk of Adverse Events in Smokers Undergoing Spinal Fusion: A Systematic Review and Meta-Analysis

STUDY DESIGN

Systematic review and meta-analysis.

OBJECTIVES

Determine if tobacco use is associated with increased risk of postoperative adverse events within 90 days in patients undergoing spinal fusion surgery.

METHODS

Databases were queried to identify cohort studies that directly compared smokers with non-smokers and provided the absolute number of adverse events and the population at risk. Data quality was evaluated using the Quality in Prognosis Studies tool. Risk ratios (RR) and 95% confidence intervals were calculated and compared between studies. The grading of recommendation, assessment, development and evaluation (GRADE) criteria were used to assess the strength of the evidence.

RESULTS

Seventeen studies assessing 37 897 participants met the inclusion criteria. Of these, 10 031 (26.5%) were smokers and 27 866 (73.5%) were nonsmokers. The mean age for the study population was 58 years, and 45% were males. Smoking was not associated with increased risk of one or more major adverse events within 90 days following spine surgery (seven studies, pooled RR 1.13, 95% CI [.75-1.71], I2 = 41%). However, smoking was significantly associated with one or more major adverse events in ≤2 level fusion (three studies, pooled RR 2.46, 95% CI [1.18-5.12], I2 = 0%), but not in fusions of ≥3 levels (four studies, pooled RR .87, 95% CI [.70-1.08], I2 = 0%). Additionally, there was no statistically significant association between smoking and any adverse event, nor increased reoperation risk due to adverse events.

CONCLUSIONS

In this meta-analysis, tobacco use was not associated with a statistically significant increased risk of adverse events within 90 days in patients undergoing spinal fusion surgery. Our results are limited by the variable reporting methodology for both complication rates as well as smoking incidence between the included individual studies.

Racial disparities in arthroscopic rotator cuff repair: an analysis of utilization and perioperative outcomes

Background

There remains a paucity of literature addressing racial disparities in utilization and perioperative metrics in arthroscopic rotator cuff repair procedures.

Methods

The American College of Surgeons National Surgical Quality Improvement Program database was used to evaluate patients undergoing arthroscopic rotator cuff repair from 2010 to 2019. Baseline demographics, utilization trends, and perioperative measures, including adverse events, operative time, length of hospital stay, days from operation to discharge, and readmission, were analyzed.

Results

Of 42,443 included patients, 38,090 (89.7%) were White, and 4353 (10.3%) were Black or African American. Black or African American patients had a significantly higher percentage of diabetes mellitus (23.6% vs. 15.6%), smoking (16.9% vs. 14.8%), congestive heart failure (0.3% vs. 0.1%), and hypertension (59.2% vs. 45.9%). In addition, logistic regression showed that Black or African American patients had increased odds of longer operative time (adjusted rate ratio 1.07, 95% confidence interval 1.05-1.08) and time from operation to discharge (adjusted rate ratio 1.19, 95% confidence interval 1.04-1.37). Disparities in relative utilization decreased as the proportion of Black or African American patients undergoing arthroscopic rotator cuff repair increased (7.4% in 2010 vs. 10.4% in 2019) compared with White patients (P _trend < .0001).

Conclusion

Racial disparities exist regarding baseline comorbidities and perioperative metrics in arthroscopic rotator cuff repair. Further investigation is needed to fully understand and address the causes of these inequalities to provide equitable care.

Relationship between smoking and postoperative complications of cervical spine surgery: a systematic review and meta-analysis

To determine whether smoking has adverse effects on postoperative complications following spine cervical surgery (PROSPERO 2021: CRD42021269648). We searched PubMed, Embase, Cochrane Library, and Web of Science through 13 July 2021 for cohort and case–control studies that investigated the effect of smoking on postoperative complications after cervical spine surgery. Two researchers independently screened the studies and extracted data according to the selection criteria. The meta-analysis included 43 studies, including 27 case–control studies and 16 cohort studies, with 10,020 patients. Pooled estimates showed that smoking was associated with overall postoperative complications (effect estimate [ES] = 1.99, 95% confidence interval [CI]: 1.62–2.44, p < 0.0001), respiratory complications (ES = 2.70, 95% CI: 1.62–4.49, p < 0.0001), reoperation (ES = 2.06, 95% CI: 1.50–2.81, p < 0.0001), dysphagia (ES = 1.49, 95% CI: 1.06–2.10, p = 0.022), wound infection (ES = 3.21, 95% CI: 1.62–6.36, p = 0.001), and axial neck pain (ES = 1.98, 95% CI: 1.25–3.12, p = 0.003). There were no significant differences between the smoking and nonsmoking groups in terms of fusion (ES = 0.97, 95% CI: 0.94–1.00, p = 0.0097), operation time (weighted mean difference [WMD] = 0.08, 95% CI: −5.54 to 5.71, p = 0.977), estimated blood loss (WMD = −5.31, 95% CI: −148.83 to 139.22, p = 0.943), length of hospital stay (WMD = 1.01, 95% CI: −2.17 to 4.20, p = 0.534), Visual Analog Scale-neck pain score (WMD = −0.19, 95% CI: −1.19 to 0.81, p = 0.707), Visual Analog Scale-arm pain score (WMD = −0.50, 95% CI: −1.53 to 0.53, p = 0.343), Neck Disability Index score (WMD = 11.46, 95% CI: −3.83 to 26.76, p = 0.142), or Japanese Orthopedic Association Scores (WMD = −1.75, 95% CI: −5.27 to 1.78, p = 0.332). Compared with nonsmokers, smokers seem to be more significantly associated with overall complications, respiratory complications, reoperation, longer hospital stay, dysphagia, wound infection and axial neck pain after cervical spine surgery. It is essential to provide timely smoking cessation advice and explanation to patients before elective cervical spine surgery.

The Impact of Smoking Cessation Therapy on Lumbar Fusion Outcomes

OBJECTIVE

While there are several reports on the impact of smoking tobacco on spinal fusion outcomes, there is minimal literature on the influence of modern smoking cessation therapies on such outcomes. Our study explores the outcomes of single-level lumbar fusion surgery in active smokers and in smokers undergoing recent cessation therapy.

METHODS

MARINER30, an all-payer claims database, was utilized to identify patients undergoing single-level lumbar fusions between 2010 and 2019. The primary outcomes were the rates of any complication, symptomatic pseudarthrosis, need for revision surgery, and all-cause readmission within 30 and 90 days.

RESULTS

The exact matched population analyzed in this study contained 31,935 patients undergoing single-level lumbar fusion with 10,645 (33%) in each of the following groups: (1) active smokers; (2) patients on smoking cessation therapy; and (3) those without any smoking history. Patients undergoing smoking cessation therapy have reduced odds of developing any complication following surgery (odds ratio 0.86, 95% confidence interval 0.80-0.93) when compared with actively smoking patients. Nonsmokers and patients on cessation therapy had a significantly lower rate of any complication compared with the smoking group (9.5% vs. 17% vs. 19%, respectively).

CONCLUSIONS

When compared with active smoking, preoperative smoking cessation therapy within 90 days of surgery decreases the likelihood of all-cause postoperative complications. However, there were no between-group differences in the likelihood of pseudarthrosis, revision surgery, or readmission within 90 days.

The Risk of Nonunion in Smokers Revisited: A Systematic Review and Meta-Analysis

STUDY DESIGN

Systemic review and meta-analysis.

OBJECTIVE

To review and establish the effect of tobacco smoking on risk of nonunion following spinal fusion.

METHODS

A systematic search of Medline, Embase, Cochrane Central Register of Controlled Trials, and the Cochrane Database of Systematic Reviews from inception to December 31, 2020, was conducted. Cohort studies directly comparing smokers with nonsmokers that provided the number of nonunions and fused segments were included. Following data extraction, the risk of bias was assessed using the Quality in Prognosis Studies Tool, and the strength of evidence for nonunion was evaluated using the GRADE working group criteria. All data analysis was performed in Review Manager 5, and a random effects model was used.

RESULTS

Twenty studies assessing 3009 participants, which included 1117 (37%) smokers, met inclusion criteria. Pooled analysis found that smoking was associated with increased risk of nonunion compared to not smoking ≥1 year following spine surgery (RR 1.91, 95% CI 1.56 to 2.35). Smoking was significantly associated with increased nonunion in those receiving either allograft (RR 1.39, 95% CI 1.12 to 1.73) or autograft (RR 2.04, 95% CI 1.54 to 2.72). Both multilevel and single level fusions carried increased risk of nonunion in smokers (RR 2.30, 95% CI 1.64 to 3.23; RR 1.79, 95% CI 1.12 to 2.86, respectively).

CONCLUSION

Smoking status carried a global risk of nonunion for spinal fusion procedures regardless of follow-up time, location, number of segments fused, or grafting material. Further comparative studies with robust methodology are necessary to establish treatment guidelines tailored to smokers.

Methodological aspects of a randomized within-patient concurrent controlled design for clinical trials in spine surgery

INTRODUCTION

Randomized controlled trials are considered the highest level of evidence, but their feasibility in the surgical field is severely hampered by methodological and practical issues. Concurrent comparison between the experimental and control conditions within the same patient can be an effective strategy to mitigate some of these challenges and improve generalizability, mainly by the elimination of between-patient variability and reduction of the required sample size. This article aims (1) to describe the methodological aspects of a randomized within-patient controlled trial and (2) to quantify the added value of this design, based on a recently completed randomized within-patient controlled trial on bone grafts in instrumented lumbar posterolateral spinal fusion.

METHODS

Boundary conditions for the application of the randomized within-patient controlled trial design were identified. Between-patient variability was quantified by the intraclass correlation coefficient and concordance in the primary fusion outcome. Sample size, study duration and costs were compared with a classic randomized controlled trial design.

RESULTS

Boundary conditions include the concurrent application of the experimental and control conditions to identical but physically separated sites. Moreover, the outcome of interest should be local, uncorrelated and independently assessable. The spinal fusion outcomes within a patient were found to be more similar than between different patients (intraclass correlation coefficient 32% and concordance 64%), demonstrating a clear effect of patient-related factors. The randomized within-patient controlled trial design allowed a reduction of the sample size to one-third of a parallel-group randomized controlled trial, thereby halving the trial duration and costs.

CONCLUSION

When suitable, the randomized within-patient controlled trial is an efficient design that provides a solution to some of the considerable challenges of a classic randomized controlled trial in (spine) surgery. This design holds specific promise for efficacy studies of non-active bone grafts in instrumented posterolateral fusion surgery.

Smoking Is Associated With Lower Satisfaction in Nondiabetic Patients Undergoing Minimally Invasive Single-level Transforaminal Lumbar Interbody Fusion

STUDY DESIGN

This was a retrospective review of prospectively collected registry data.

OBJECTIVE

The objective of this study was to investigate the effect of smoking on 2 years postoperative functional outcomes, satisfaction, and radiologic fusion in nondiabetic patients undergoing minimally invasive transforaminal lumbar interbody fusion (TLIF) for degenerative spine conditions.

SUMMARY OF BACKGROUND DATA

There is conflicting data on the effect of smoking on long-term functional outcomes following lumbar fusion. Moreover, there remains a paucity of literature on the influence of smoking within the field of minimally invasive spine surgery.

METHODS

Prospectively collected registry data of nondiabetic patients who underwent primary single-level minimally invasive TLIF in a single institution was reviewed. Patients were stratified based on smoking history. All patients were assessed preoperatively and postoperatively using the Numerical Pain Rating Scale for back pain and leg pain, Oswestry Disability Index, Short-Form 36 Physical and Mental Component Scores. Satisfaction was assessed using the North American Spine Society questionnaire. Radiographic fusion rates were compared.

RESULTS

In total, 187 patients were included, of which 162 were nonsmokers, and 25 had a positive smoking history. In our multivariate analysis, smoking history was insignificant in predicting for minimal clinically important difference attainment rates in Physical Component Score and fusion grading outcomes. However, in terms of satisfaction score, positive smoking history remained a significant predictor (odds ratio=4.7, 95% confidence interval: 1.10-20.09, P=0.036).

CONCLUSIONS

Nondiabetic patients with a positive smoking history had lower satisfaction scores but comparable functional outcomes and radiologic fusion 2 years after single-level TLIF. Thorough preoperative counseling and smoking cessation advice may help to improve patient satisfaction following minimally invasive spine surgery.

LEVEL OF EVIDENCE

Level III-nonrandomized cohort study.

Comparison of Perioperative Complications Following Surgical Treatment of Shoulder Instability

Background

Surgical repair for shoulder instability includes arthroscopic Bankart, open Bankart, and Latarjet-Bristow.

Methods

This is a cohort study of patients who underwent arthroscopic Bankart, open Bankart, or Latarjet-Bristow procedures that were identified within the National Surgical Quality Improvement Program database (2007-2019). Unadjusted and adjusted analyses were performed (α = 0.05). Outcomes included 30-day adverse events, readmission, and operative time.

Results

This study included 10,955 patients (9128 arthroscopic Bankart, 1148 open Bankart, and 679 Latarjet-Bristow). Compared with arthroscopic Bankart, Latarjet-Bristow had longer operative times (129.96 [95% CI: 126.49-133.43] vs. 86.35 [85.51-87.19] minutes), along with a higher percentage of serious adverse events (2.5% vs. 0.4%), reoperation (1.9% vs. 0.1%), readmission (1.8% vs. 0.3%), thromboembolic complications (0.4% vs. 0.1%), and sepsis (0.4% vs. 0.0%) (P < .05 for all). Open Bankart had longer operative times (98.17 [95.52-100.82] vs. 86.35 [85.51-87.19] minutes) and a higher percentage of sepsis (0.2% vs. 0.0%) (P < .05 both). Latarjet-Bristow had increased odds of a serious adverse event (odds ratio [OR]: 7.68 [4.19-14.07]), reoperation (OR: 17.32 [7.58-39.56]), readmission (OR: 5.73 [2.84-11.54]), and deep wound complications (OR: 14.98 [3.92-57.23]) (P < .05 for all). In comparing the relative utilization of arthroscopic versus open Bankart, arthroscopic Bankart increased (83.4% to 91.2%) while open Bankart decreased (16.6% to 8.8%) from the 2011-2013 time period to 2017-2019 (P_trend < .001).

Conclusion

In addition to a low complication rate, the relative utilization of arthroscopic Bankart increased compared with open Bankart over the past decade. Furthermore, Latarjet-Bristow was associated with a higher incidence of serious adverse events than arthroscopic Bankart.

LUMBAR ARTHRODESIS IN DEGENERATIVE SPINE: POST OPERATIVE RESULTS AND RADIOGRAPHIC EVALUATION

ABSTRACT Objective: To relate the radiographic fusion rate and the surgical results in patients undergoing posterolateral arthrodesis with instrumentation of the lumbar spine for the treatment of degenerative disorders. Method: A descriptive, retrospective, case series, observational study, based on medical records and imaging studies of 76 patients over 18 years of age (39 to 88 years) who underwent posterolateral lumbar arthrodesis. Data related to the presence of comorbidities were compiled and clinical outcomes were measured using specific questionnaires collected pre-surgical and 1 year after surgery. Fusion quality, as described by Christensen, was assessed from radiographic images by two examiners. The VAS, EQ-5D and Roland Morris questionnaires were used preoperatively and 1 year after surgery to assess pain, quality of life and function, respectively. Result: It was observed improvement in pain, function and quality of life after 1 year post-surgical. Pain, measured by VAS, had a reduction from 7.92 to 3.16 (p-value <0.001), the function evaluated by the Roland Morris score, also showed a reduction from 14.90 to 7.06 (p-value <0.001) . Culminating with the improvement in quality of life, measured by the EQ-5D, where there was a median increase in the score from 0.5672 to 0.7002 (p-value = 0.002). Conclusion: The absence of radiographic fusion has no direct correlation with worse results in clinical outcomes at 01 year after surgery. Most patients showed clinical improvement with no statistical difference in relation to cases in which bone fusion was obtained. Level of evidence IV; retrospective observation.

Effects of Caffeine on Intervertebral Disc Cell Viability in a Whole Organ Culture Model

STUDY DESIGN

Controlled laboratory study.

OBJECTIVE

To investigate the impact of exposure to physiologically relevant caffeine concentrations on intervertebral disc (IVD) cell viability and extracellular matrix composition (ECM) in a whole organ culture model as potential contributing mechanisms in development and progression of IVD disorders in humans. Primary outcome measures were IVD viable cell density (VCD) and ECM composition.

METHODS

A total of 190 IVD whole organ explants from tails of 16 skeletally mature rats-consisting of cranial body half, endplate, IVD, endplate, and caudal body half-were harvested. IVD explants were randomly assigned to 1 of 2 groups: uninjured (n = 90) or injured (20G needle disc puncture/aspiration method, n = 100). Explants from each group were randomly assigned to 1 of 3 treatment groups: low caffeine (LCAF: 5 mg/L), moderate caffeine (MCAF: 10 mg/L), and high caffeine (HCAF: 15 mg/L) concentrations.

RESULTS

Cell viability was significantly higher in the low-caffeine group compared with the high-caffeine group at day 7 (P = .037) and in the low-caffeine group compared with the medium- and high-caffeine groups at day 21 (P ≤ .004). Analysis of ECM showed that all uninjured and control groups had significantly higher (P < .05) glycosaminoglycan concentrations compared with all injured groups. Furthermore, we observed a temporal, downward trend in proteoglycan to collagen ratio for the caffeine groups.

CONCLUSIONS

Caffeine intake may be a risk factor for IVD degeneration, especially in conjunction with disc injury. Mechanisms for caffeine associated disc degeneration may involve cell and ECM, and further studies should elucidate mechanistic pathways and potential benefits for caffeine restriction.

Clinical practice guideline: evidence, recommendations and algorithm for the preoperative optimization of anemia, hyperglycemia and smoking

Preoperative optimization has not been explored comprehensively in the surgical literature, as this responsibility has often been divided among surgery, anesthesia and medicine. We developed an evidence-based clinical practice guideline to summarize existing evidence and present diagnostic and treatment algorithms for use by surgeons caring for patients scheduled to undergo major elective surgery. We focus on 3 common comorbid conditions seen across surgical specialties - anemia, hyperglycemia and smoking - as these conditions increase complication rates in patients undergoing major surgery and can be optimized successfully as soon as 6-8 weeks before surgery. With the ability to address these conditions earlier in the patient journey, surgeons can positively affect patient outcomes. The aim of this guideline is to bring optimization in the preoperative period under the existing umbrella of evidence-based surgical care.

Comparing porous tantalum fusion implants and iliac crest bone grafts for spondylodesis of thoracolumbar burst fractures: Prospectice Cohort study

The aim of this study was to compare two different techniques of performing one-level spondylodesis for thoracolumbar burst fractures using either an autologous iliac crest bone graft (ICBG) or a porous tantalum fusion implant (PTFI). In a prospective nonrandomized study, 44 patients (20 women, 24 men; average age 43.1 ± 13.2 years) suffering from severe thoracolumbar burst fractures were treated with combined anterior–posterior stabilization. An ICBG was used in 21 cases, and a PTFI was used in the other 23 cases. A two-year clinical and radiographic follow-up was carried out. There were no statistically significant differences in age, sex, localization/classification of the fracture, or visual analog scale (VAS) before injury between the two groups. All 44 patients were followed up for an average period of 533 days (range 173–1567). The sagittal spinal profile was restored by an average of 11.1° (ICBG) vs. 14.3° (PTFI) (monosegmental Cobb angle). Loss of correction until the last follow-up tended to be higher in the patients treated with ICBG than in those treated with PTFI (mean: 2.8° vs. 1.6°). Furthermore, significantly better restoration of the sagittal profile was obtained with the PTFI than with the iliac bone graft at the long-term follow-up (mean: ICBG 7.8°, PTFI 12.3°; p < 0.005). Short-segment posterior instrumentation combined with anterior one-level spondylodesis using either an ICBG or a PTFI resulted in sufficient correction of posttraumatic segmental kyphosis. PTFI might be a good alternative for autologous bone grafting and prevent donor site morbidities.

The effect of smoking on achieving meaningful clinical outcomes one year after lumbar tubular microdecompression: a matched-pair cohort analysis

BACKGROUND CONTEXT

There has been a shift in the spine literature in reporting meaningful outcomes, including meaningful clinically important difference (MCID), after surgery. The evidence on the effect of tobacco smoking at the time of lumbar tubular microdecompression (LTMD) on meaningful outcomes is limited.

PURPOSE

To compare differences in 1-year functional outcomes and rates of achieving MCID between current smokers and non-smokers who underwent LTMD for lumbar spinal stenosis (LSS).

STUDY DESIGN

A nested case control study to compare the difference in patient reported outcomes (PROs) between smokers and non-smokers 1-year after undergoing LTMD.

PATIENT SAMPLE

This study included patients that underwent single level LTMD by a single surgeon between January 2014 through August 2019.

OUTCOME MEASURES

Preoperative and postoperative PROs were recorded using the questionnaires EQ-5D, Oswestry Disability Index (ODI), and the visual analog scale (VAS) for back pain and leg pain. The MCID was also used.

METHODS

Current tobacco smokers at the time of surgery were matched 1:2 to non-smokers by age (+/- 1year). Preoperative and postoperative functional scores were compared between the two groups using independent t-tests. Additionally, thresholds for achieving MCID were calculated for each individual functional score, and were compared using Fisher's exact test.

RESULTS

Of the 183 patients with 1-year follow-up who met inclusion criteria, 35 patients were identified as smokers and were matched to 70 non-smokers. No statistical differences were identified between age, BMI, or gender. Comparison of preoperative PROs showed no statistically significant differences between smokers and non-smokers (p>0.05 for all), while smokers had statistically lower EQ-5D (p<0.001) and higher ODI (p=0.05), VAS back (p=0.033), and VAS leg (p=0.03) score averages at a minimum of one year follow-up. Evaluation of meaningful outcomes demonstrated non-smokers had higher rates of achieving MCID on at least 1 threshold score as compared to smokers (98.5% vs. 91.1%; p=0.043).

CONCLUSIONS

Current smokers at the time of surgery have inferior postoperative EQ-5D scores, increased pain and disability, and lower odds of achieving the MCID at 1-year after undergoing LTMD when compared to patients without any smoking history.

The impact of smoking on outcomes following anterior cervical fusion-nonfusion hybrid surgery: a retrospective single-center cohort study

BACKGROUND

There is mixed evidence for the impact of cigarette smoking on outcomes following anterior cervical surgery. It has been reported to have a negative impact on healing after multilevel anterior cervical discectomy and fusion, however, segmental mobility has been suggested to be superior in smokers who underwent one- or two-level cervical disc replacement. Hybrid surgery, including anterior cervical discectomy and fusion and cervical disc replacement, has emerged as an alternative procedure for multilevel cervical degenerative disc disease. This study aimed to examine the impact of smoking on intermediate-term outcomes following hybrid surgery.

METHODS

Radiographical and clinical outcomes of 153 patients who had undergone continuous two- or three-level hybrid surgery were followed-up to a minimum of 2-years post-operatively. The early fusion effect, 1-year fusion rate, the incidence of bone loss and heterotopic ossification, as well as the clinical outcomes were compared across three smoking status groups: (1) current smokers; (2) former smokers; (3) nonsmokers.

RESULTS

Clinical outcomes were comparable among the three groups. However, the current smoking group had a poorer early fusion effect and 1-year fusion rate (P < 0.001 and P < 0.035 respectively). Both gender and smoking status were considered as key factors for 1-year fusion rate. Upon multivariable analysis, male gender (OR = 6.664, 95% CI: 1.248-35.581, P = 0.026) and current smoking status (OR = 0.009, 95% CI: 0.020-0.411, P = 0.002) were significantly associated with 1-year fusion rate. A subgroup analysis demonstrated statistically significant differences in both early fusion process (P < 0.001) and the 1-year fusion rate (P = 0.006) across the three smoking status groups in female patients. Finally, non-smoking status appeared to be protective against bone loss (OR = 0.427, 95% CI: 0.192-0.947, P = 0.036), with these patients likely to have at least one grade lower bone loss than current smokers.

CONCLUSIONS

Smoking is associated with poor outcomes following hybrid surgery for multilevel cervical disc disease. Current smokers had the poorest fusion rate and most bone loss, but no statistically significant differences were seen in clinical outcomes across the three groups.

The Effect of Smoking on the Fusion Rate of Spinal Fusion Surgery: A Systematic Review and Meta-Analysis

OBJECTIVE

To conduct a systematic review and meta-analysis comparing the fusion rate after spinal fusion surgery between smokers and nonsmokers.

METHODS

We searched PubMed, Embase, Cochrane Library, and Web of Science electronic databases through March 10, 2021 for cohort and case-control studies assessing the effect of smoking on the fusion rate of spinal fusion surgery. Two researchers independently screened the literature and extracted data according to the inclusion and exclusion criteria. Statistical analysis was performed using RevMan, version 5.4.

RESULTS

A total of 26 studies, including 4 case-control studies and 22 cohort studies, with 4409 patients, were included in the present meta-analysis. Follow-up was at least 6 months. Overall, the pooled results demonstrated that the fusion rate of smokers after spinal fusion was significantly lower than that of nonsmokers. The odds ratio (OR) was 0.55 (95% confidence interval [CI] 0.45-0.67, P < 0.0001). Subgroup analyses by fusion level showed the adverse effect of smoking on the fusion rate at single level (OR 0.61, 95% CI 0.41-0.91, P = 0.02) was more significant than that of multiple levels (OR 0.55, 95% CI 0.38-0.80, P = 0.0010). Subgroup analysis according to the type of bone graft revealed an apparent association between smoking and fusion rate in the autograft subgroup (OR 0.47, 95% CI 0.33-0.66, P < 0.0001) but not in the allograft subgroup (OR 0.69, 95% CI 0.47-1.01, P = 0.06).

CONCLUSIONS

The fusion rate of smokers is significantly lower than that of nonsmokers in spinal fusion surgery. Smokers should be encouraged to quit smoking to improve the outcome of spinal fusion surgery.

Does Smoking Affect Short-Term Patient-Reported Outcomes After Lumbar Decompression?

STUDY DESIGN

Retrospective cohort study.

OBJECTIVE

The goal of this study was to determine how smoking status influences patient-reported outcome measurements (PROMs) in patients undergoing lumbar decompression surgery.

METHODS

Patients undergoing lumbar decompression between 1 to 3 levels at a single-center, academic hospital were retrospectively identified. Patients <18 years old, and those undergoing surgery for infection, trauma, tumor, or revision, with less than 12 months of follow-up were excluded. Patients were divided into 3 groups: (1) never smokers (NSs); (2) current smokers (CSs); and (3) former smokers (FSs). PROMs analyzed included the Physical Component Score and Mental Component Score of the Short Form-12 Health Survey, the Oswestry Disability Index, and Visual Analogue Scale Back and Leg pain scores. One-way ANOVA was used to compare preoperative and postoperative scores between smoking groups, and multiple linear regression analysis was performed to determine whether smoking status predicted change in each outcome score, controlling for factors such as age, sex, body mass index, and other clinical variables. A P value <.05 was considered to be significant.

RESULTS

A total of 195 patients were included in the final cohort, with 121 (62.1%) patients in the NS group, 22 (11.3%) in the CS group, and 52 (26.6%) in the FS group. There were no significant differences between groups at baseline or postoperatively. Smoking status was also not a significant predictor of change in any outcome scores over time on multivariate analysis.

CONCLUSION

These results suggest that smoking status does not significantly affect short-term complications or outcomes in patients undergoing lumbar decompression surgery.

Understanding the Future Prospects of Synergizing Minimally Invasive Transforaminal Lumbar Interbody Fusion Surgery with Ceramics and Regenerative Cellular Therapies

Transforaminal lumber interbody fusion (TLIF) is the last resort to address the lumber degenerative disorders such as spondylolisthesis, causing lower back pain. The current surgical intervention for these abnormalities includes open TLIF. However, in recent years, minimally invasive TLIF (MIS-TLIF) has gained a high momentum, as it could minimize the risk of infection, blood loss, and post-operative complications pertaining to fusion surgery. Further advancement in visualizing and guiding techniques along with grafting cage and materials are continuously improving the safety and efficacy of MIS-TLIF. These assistive techniques are also playing a crucial role to increase and improve the learning curve of surgeons. However, achieving an appropriate output through TLIF still remains a challenge, which might be synergized through 3D-printing and tissue engineering-based regenerative therapy. Owing to their differentiation potential, biomaterials such as stem/progenitor cells may contribute to restructuring lost or damaged tissues during MIS-TLIF, and this therapeutic efficacy could be further supplemented by platelet-derived biomaterials, leading to improved clinical outcomes. Thus, based on the above-mentioned strategies, we have comprehensively summarized recent developments in MIS-TLIF and its possible combinatorial regenerative therapies for rapid and long-term relief.

Adverse impact of smoking on the spine and spinal surgery

Background

Tobacco smokers and companies are well aware that smoking increases the risks for cancers, vascular morbidity, and early mortality. This is a review of the plethora of adverse effects chronic smoking has on spinal tissues and spinal surgery.

Methods

Medline (PubMed) and Google Scholar databases were searched for pertinent literature through keywords related to smoking, spondylosis, and spinal surgery.

Results

Smoking accelerates spondylosis by impairing spinal tissue vascular supply through atherosclerosis and thrombosis, while inducing local hypoxia, inflammation, proteolysis, and cell loss. It, thus, compromises disc, cartilage, synovium, bone, and blood vessels. It can lead to early surgery, delayed wound healing, increased surgical site infection, failed fusion, more re-operations, and chronic spinal pain.

Conclusion

There is ample evidence to support surgeons' declining to operate on chronic smokers. The need for immediate and permanent smoking cessation and its potential benefits should be emphasized for the patient considering or who has undergone spinal surgery.

Pathway for enhanced recovery after spinal surgery-a systematic review of evidence for use of individual components

Background

Enhanced recovery in spinal surgery (ERSS) has shown promising improvements in clinical and economical outcomes. We have proposed an ERSS pathway based on available evidence. We aimed to delineate the clinical efficacy of individual pathway components in ERSS through a systematic narrative review.

Methods

We included systematic reviews and meta-analysis, randomized controlled trials, non-randomized controlled studies, and observational studies in adults and pediatric patients evaluating any one of the 22 pre-defined components. Our primary outcomes included all-cause mortality, morbidity outcomes (e.g., pulmonary, cardiac, renal, surgical complications), patient-reported outcomes and experiences (e.g., pain, quality of care experience), and health services outcomes (e.g., length of stay and costs). Following databases (1990 onwards) were searched: MEDLINE, EMBASE, and Cochrane Library (Cochrane Database of Systematic Reviews and CENTRAL). Two authors screened the citations, full-text articles, and extracted data. A narrative synthesis was provided. We constructed Evidence Profile (EP) tables for each component of the pathway, where appropriate information was available. Due to clinical and methodological heterogeneity, we did not conduct a meta-analyses. GRADE system was used to classify confidence in cumulative evidence for each component of the pathway.

Results

We identified 5423 relevant studies excluding duplicates as relating to the 22 pre-defined components of enhanced recovery in spinal surgery. We included 664 studies in the systematic review. We identified specific evidence within the context of spinal surgery for 14/22 proposed components. Evidence was summarized in EP tables where suitable. We performed thematic synthesis without EP for 6/22 elements. We identified appropriate societal guidelines for the remainder of the components.

Conclusions

We identified the following components with high quality of evidence as per GRADE system: pre-emptive analgesia, peri-operative blood conservation (antifibrinolytic use), surgical site preparation and antibiotic prophylaxis. There was moderate level of evidence for implementation of prehabilitation, minimally invasive surgery, multimodal perioperative analgesia, intravenous lignocaine and ketamine use as well as early mobilization. This review allows for the first formalized evidence-based unified protocol in the field of ERSS.

Further studies validating the multimodal ERSS framework are essential to guide the future evolution of care in patients undergoing spinal surgery.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12871-021-01281-1.

Implementation of a systematic tobacco treatment protocol in a surgical outpatient setting: a feasibility study

Background

Smoking cessation programs started as late as 4 weeks before surgery reduce perioperative morbidity and death, yet outpatient clinic interventions are rarely provided. Our aim was to evaluate the feasibility of implementing a tobacco treatment protocol designed for an outpatient surgical setting.

Methods

We completed a pre–post feasibility study of the implementation of a systematic, evidence-based tobacco treatment protocol in an outpatient colorectal surgery clinic. Outcomes included smoking prevalence, pre- and postimplementation smoker identification and intervention rates, recruitment, retention, smoking cessation and provider satisfaction.

Results

Preimplementation, 15.5% of 116 surveyed patients were smokers. Fewer than 10% of surveyed patients reported being asked about smoking, and none were offered any cessation intervention. Over a 16-month postimplementation period, 1198 patients were seen on 2103 visits. Of these, 950 (79.3%) patients were asked smoking status on first visit and 1030 (86.0%) were asked on at least 1 visit. Of 169 identified smokers, 99 (58.6%) were referred to follow-up support using an opt-out approach. At 1-, 3- and 6-month follow- up, intention-to-quit rates among 78 enrolled patients were 24.4%, 22.9% and 19.2%, respectively. Postimplementation staff surveys reported that the protocol was easy to use, that staff would use it again and that it had positive patient responses.

Conclusion

Implementation of our smoking cessation protocol in an outpatient surgical clinic was found to be feasible and used minimal clinic resources. This protocol could lead to increases in identification and documentation of smoking status, delivery of smoking cessation interventions and rates of smoking reduction and cessation.

Diagnostic Accuracy of Thresholds Less Than or Equal to 8 mA in Pedicle Screw Testing During Lumbar Spine Procedures to Predict New Postoperative Lower Extremity Neurological Deficits

STUDY DESIGN

Retrospective observational study.

OBJECTIVE

It has been shown that pedicle screw stimulation thresholds less than or equal to 8 mA yield a very high diagnostic accuracy of detecting misplaced screws in spinal surgery. In our study, we determined clinical implications of low stimulation thresholds.

SUMMARY OF BACKGROUND DATA

Posterior lumbar spinal fusions (PSF), using pedicle screws, are performed to treat many spinal pathologies, but misplaced pedicle screws can result in new postoperative neurological deficits.

METHODS

Patients with pedicle screw stimulation testing who underwent PSF between 2010 and 2012 at the University of Pittsburgh Medical Center (UPMC) were included in the study. We evaluated the sensitivity, specificity, and diagnostic odds ratio (DOR) to determine how effectively low pedicle screw responses predict new postoperative lower extremity neurological deficits.

RESULTS

One thousand one hundred seventy nine eligible patients underwent 8584 pedicle screw stimulations with lower extremity somatosensory evoked potentials (LE SSEP) monitoring for lumbar fusion surgery. One hundred twenty one of these patients had 187 pedicle screws with a stimulation response at a threshold less than or equal to 8 mA. Smoking had a significant correlation to pedicle screw stimulation less than or equal to 8 mA (P = 0.012). A threshold of less than or equal to 8 mA had a sensitivity/specificity of 0.32/0.90 with DOR of 4.34 [1.83, 10.27] and an area under the ROC curve (AUC) of 0.61 [0.49, 0.74]. Patients with screw thresholds less than or equal to 8 mA and abnormal baselines had a DOR of 9.8 [95% CI: 2.13-45.17] and an AUC of 0.73 [95% CI: 0.50-0.95].

CONCLUSION

Patients with pedicle screw stimulation thresholds less than or equal to 8 mA are 4.34 times more likely to have neurological clinical manifestations. Smoking and LE deficits were shown to be significantly correlated with pedicle screw stimulation thresholds less than or equal to 8 mA. Low stimulation thresholds result in a high specificity of 90%. Pedicle screw stimulation less than or equal to 8 mA can serve as an accurate rule in test for postoperative neurological deficit, warranting reevaluation of screw placement and/or replacement intraoperatively.Level of Evidence: 3.

Growth Factors, Carrier Materials, and Bone Repair

This chapter provides an overview of the growth factors active in bone regeneration and healing. Both normal and impaired bone healing are discussed, with a focus on the spatiotemporal activity of the various growth factors known to be involved in the healing response. The review highlights the activities of most important growth factors impacting bone regeneration, with a particular emphasis on those being pursued for clinical translation or which have already been marketed as components of bone regenerative materials. Current approaches the use of bone grafts in clinical settings of bone repair (including bone grafts) are summarized, and carrier systems (scaffolds) for bone tissue engineering via localized growth factor delivery are reviewed. The chapter concludes with a consideration of how bone repair might be improved in the future.

A Cost-Effectiveness Analysis of Smoking-Cessation Interventions Prior to Posterolateral Lumbar Fusion

BACKGROUND

Smoking cessation represents an opportunity to reduce both short and long-term effects of smoking on complications after lumbar fusion and smoking-related morbidity and mortality. However, the cost-effectiveness of smoking-cessation interventions prior to lumbar fusion is not fully known.

METHODS

We created a decision-analytic Markov model to evaluate the cost-effectiveness of 5 smoking-cessation strategies (behavioral counseling, nicotine replacement therapy [NRT], bupropion or varenicline monotherapy, and a combined intervention) prior to single-level, instrumented lumbar posterolateral fusion (PLF) from the health payer perspective. Probabilities, costs, and utilities were obtained from published sources. We calculated the costs and quality-adjusted life years (QALYs) associated with each strategy over multiple time horizons and accounted for uncertainty with probabilistic sensitivity analyses (PSAs) consisting of 10,000 second-order Monte Carlo simulations.

RESULTS

Every smoking-cessation intervention was more effective and less costly than usual care at the lifetime horizon. In the short term, behavioral counseling, NRT, varenicline monotherapy, and the combined intervention were also cost-saving, while bupropion monotherapy was more effective but more costly than usual care. The mean lifetime cost savings for behavioral counseling, NRT, bupropion monotherapy, varenicline monotherapy, and the combined intervention were $3,291 (standard deviation [SD], $868), $2,571 (SD, $479), $2,851 (SD, $830), $6,767 (SD, $1,604), and $34,923 (SD, $4,248), respectively. The minimum efficacy threshold (relative risk for smoking cessation) for lifetime cost savings varied from 1.01 (behavioral counseling) to 1.15 (varenicline monotherapy). A PSA revealed that the combined smoking-cessation intervention was always more effective and less costly than usual care.

CONCLUSIONS

Even brief smoking-cessation interventions yield large short-term and long-term cost savings. Smoking-cessation interventions prior to PLF can both reduce costs and improve patient outcomes as health payers/systems shift toward value-based reimbursement (e.g., bundled payments) or population health models.

LEVEL OF EVIDENCE

Economic Level II. See Instructions for Authors for a complete description of levels of evidence.

Development and Validation of Cervical Prediction Models for Patient-Reported Outcomes at 1 Year After Cervical Spine Surgery for Radiculopathy and Myelopathy

STUDY DESIGN

Retrospective analysis of prospectively collected registry data.

OBJECTIVE

To develop and validate prediction models for 12-month patient-reported outcomes of disability, pain, and myelopathy in patients undergoing elective cervical spine surgery.

SUMMARY OF BACKGROUND DATA

Predictive models have the potential to be utilized preoperatively to set expectations, adjust modifiable characteristics, and provide a patient-centered model of care.

METHODS

This study was conducted using data from the cervical module of the Quality Outcomes Database. The outcomes of interest were disability (Neck Disability Index:), pain (Numeric Rating Scale), and modified Japanese Orthopaedic Association score for myelopathy. Multivariable proportional odds ordinal regression models were developed for patients with cervical radiculopathy and myelopathy. Patient demographic, clinical, and surgical covariates as well as baseline patient-reported outcomes scores were included in all models. The models were internally validated using bootstrap resampling to estimate the likely performance on a new sample of patients.

RESULTS

Four thousand nine hundred eighty-eight patients underwent surgery for radiculopathy and 2641 patients for myelopathy. The most important predictor of poor postoperative outcomes at 12-months was the baseline Neck Disability Index score for patients with radiculopathy and modified Japanese Orthopaedic Association score for patients with myelopathy. In addition, symptom duration, workers' compensation, age, employment, and ambulatory and smoking status had a statistically significant impact on all outcomes (P < 0.001). Clinical and surgical variables contributed very little to predictive models, with posterior approach being associated with higher odds of having worse 12-month outcome scores in both the radiculopathy and myelopathy cohorts (P < 0.001). The full models overall discriminative performance ranged from 0.654 to 0.725.

CONCLUSIONS

These predictive models provide individualized risk-adjusted estimates of 12-month disability, pain, and myelopathy outcomes for patients undergoing spine surgery for degenerative cervical disease. Predictive models have the potential to be used as a shared decision-making tool for evidence-based preoperative counselling.

LEVEL OF EVIDENCE

2.

Effects of smoking on pedicle screw-based dynamic stabilization: radiological and clinical evaluations of screw loosening in 306 patients

OBJECTIVE

Cigarette smoking has been known to increase the risk of pseudarthrosis in spinal fusion. However, there is a paucity of data on the effects of smoking in dynamic stabilization following lumbar spine surgery. This study aimed to investigate the clinical outcomes and the incidence of screw loosening among patients who smoked.

METHODS

Consecutive patients who had lumbar spondylosis, recurrent disc herniations, or low-grade spondylolisthesis that was treated with 1- or 2-level surgical decompression and pedicle screw-based Dynesys dynamic stabilization (DDS) were retrospectively reviewed. Patients who did not complete the minimum 2 years of radiological and clinical evaluations were excluded. All screw loosening was determined by both radiographs and CT scans. Patient-reported outcomes, including visual analog scale (VAS) scores of back and leg pain, Japanese Orthopaedic Association (JOA) scores, and Oswestry Disability Index (ODI), were analyzed. Patients were grouped by smoking versus nonsmoking, and loosening versus intact screws, respectively. All radiological and clinical outcomes were compared between the groups.

RESULTS

A total of 306 patients (140 women), with a mean age of 60.2 ± 12.5 years, were analyzed during an average follow-up of 44 months. There were 34 smokers (9 women) and 272 nonsmokers (131 women, 48.2% more than the 26.5% of smokers, p = 0.017). Postoperatively, all the clinical outcomes improved (e.g., VAS back and leg pain, JOA scores, and ODI, all p < 0.001). The overall rate of screw loosening was 23.2% (71 patients), and patients who had loosened screws were older (61.7 ± 9.6 years vs 59.8 ± 13.2 years, p = 0.003) and had higher rates of diabetes mellitus (33.8% vs 21.7%, p = 0.038) than those who had intact DDS screws. Although the patients who smoked had similar clinical improvement (even better VAS scores in their legs, p = 0.038) and a nonsignificantly lower rate of screw loosening (17.7% and 23.9%, p = 0.416), the chances of secondary surgery for adjacent segment disease (ASD) were higher than for the nonsmokers (11.8% vs 1.5%, p < 0.001).

CONCLUSIONS

Smoking had no adverse effects on the improvements of clinical outcomes in the pedicle screw-based DDS surgery. For smokers, the rate of screw loosening trended lower (without significance), but the chances of secondary surgery for ASD were higher than for the nonsmoking patients. However, the optimal surgical strategy to stabilize the lumbar spine of smoking patients requires future investigation.

Scientific, Clinical, Regulatory, and Economic Aspects of Choosing Bone Graft/Biological Options in Spine Surgery

Spinal arthrodesis is a major element of the spinal surgeon's practice. To attain successful fusion rates, attention must be paid to spinal segment immobilization and proper selection of bone graft. Autogenous bone graft (ie, ICBG), the "gold standard," with or without graft extenders and enhancers provides the foundation for most spinal fusions. ABG is the only graft option containing all 3 factors of new bone growth: osteoconductivity, osteoinductivity, and osteogenicity. While many bone graft alternatives function well as bone graft extenders, only growth factors proteins (ie, rhBMP-2 or OP-2) function as bone graft enhancers and substitutes. The search for optimal hybrid interbody cages, bone graft substitutes, autogenous or allogenic stem cells, and nanostructure scaffolds for release of growth factors continues.

Association of Smoking and Other Factors With the Outcome of Mohs Reconstruction Using Flaps or Grafts

Importance

Smoking, a common lifestyle trait, is considered by many surgeons to be a major risk factor for postoperative complications. However, in the literature on local reconstruction, the association between smoking and the rate of postoperative complications after cutaneous tissue transfer is not well characterized.

Objective

To study the outcomes of flaps and grafts used in Mohs micrographic surgery reconstruction with respect to smoking status and patient-specific and surgery-specific variables.

Design, Setting, and Participants

This retrospective case-control study was conducted at a single tertiary referral center among 1008 patients who underwent Mohs reconstruction repaired by flap or graft between July 1, 2012, and June 30, 2016, and were selected via consecutive sampling. Cases with incomplete records or those in which a single flap or graft was used to repair multiple defects were excluded. Data analysis was performed from September 2017 to January 2018.

Main Outcomes and Measures

Postoperative acute and long-term complications. Acute complications included postsurgical infection, dehiscence, hematoma, uncontrolled bleeding, and tissue necrosis that required medical counseling or intervention. Long-term complications included functional or cosmetic outcomes that prompted the patient to request or the surgeon to offer additional intervention.

Results

Of the 1008 patients included in the study (396 women and 612 men), the median (SD) age was 70 (12) years (range, 21-90 years). A total of 128 patients (12.7%) were current smokers, 385 (38.2%) were former smokers, and 495 (49.1%) were never smokers. On multivariate logistic regression, current smoking (odds ratio [OR], 9.58; 95% CI, 3.63-25.3), former smoking (OR, 3.64; 95% CI, 1.41-9.38), larger defect size (OR, 2.25; 95% CI, 1.58-3.20), and the use of free cartilage graft (OR, 8.19; 95% CI, 2.02-33.1) were associated with increased risks of acute complications. For long-term complications, central face location (OR, 25.4; 95% CI, 6.16-106.5), use of interpolation flap or flap-graft combination (OR, 3.49; 95% CI, 1.81-6.74), larger flap size (OR, 1.42; 95% CI, 1.09-1.87), and basal cell carcinomas or other basaloid tumors (OR, 3.43; 95% CI, 1.03-11.5) were associated with an increased risk, whereas increased age (OR, 0.66 per 10-year interval; 95% CI, 0.54-0.80) was associated with decreased risk.

Conclusions and Relevance

This study suggests that both current and former smokers are at increased risk for acute postsurgical complications but that smoking status is not associated with long-term complications. These findings may allow the surgeon to better quantify the magnitude of risk and provide helpful information for patient counseling.

Level of Evidence

3.

The effect of current and former tobacco use on outcomes after primary reverse total shoulder arthroplasty

BACKGROUND

The purpose of this study was to determine the influence of current and former tobacco use on minimum 2-year clinical and radiographic outcomes after reverse total shoulder arthroplasty (RTSA).

METHODS

Review of primary RTSA patient data identified 186 patients with at least 2 years of follow-up. Patients were classified as nonsmokers (76 patients), former smokers (89 patients), or current smokers (21 patients). Assessment included preoperative and postoperative visual analog scale pain scores, American Shoulder and Elbow Surgeons scores, strength, range of motion, complications, revisions, and narcotic use. Radiographs were analyzed for signs of loosening or mechanical failure.

RESULTS

Overall mean age of the patients was 70 (48-87) years, and mean follow-up was 2.6 (2.0-5.7) years. Smokers (62.1 years) were significantly younger than nonsmokers (70.7 years) and former smokers (70.8 years; P = .00002). All patients had significant improvements in pain, American Shoulder and Elbow Surgeons score, strength, and forward flexion range of motion; however, smokers had higher visual analog scale pain scores (mean, 2.5) than nonsmokers (mean, 1.8) or former smokers (mean, 1.0; P = .014). Otherwise, no differences were found regarding any of the postoperative parameters (P > .05).

CONCLUSIONS

Aside from increased patient-reported pain, current tobacco use does not appear to negatively affect outcomes after primary RTSA. The RTSA design obviates the need for a functioning rotator cuff, possibly mitigating tobacco's negative effects previously demonstrated in rotator cuff repair and anatomic total shoulder arthroplasty. Former users obtained outcomes similar to those of nonusers, suggesting that tobacco use is a modifiable risk factor to achieve optimal pain relief after RTSA.

Fusion rate and influence of surgery-related factors in lumbar interbody arthrodesis for degenerative spine diseases: a meta-analysis and systematic review

The aim of this meta-analysis and systematic review is to summarize and critically analyze the influence of surgery-related factors in lumbar interbody fusion for degenerative spine diseases. A systematic review of the literature was carried out with a primary search being performed on Medline through PubMed. The 2009 PRISMA flowchart and checklist were taken into account. Sixty-seven articles were included in the analysis: 48 studies were level IV of evidence, whereas 19 were level III. All interbody fusion techniques analyzed have proved to reach a good fusion rate. An overall mean fusion rate of 93% (95% CI 92-95%, p < 0.001) was estimated pooling the selected studies. The influence of sagittal parameters and cages features in fusion rate was not clear. Autograft is considered the gold standard material. The use of synthetic bone substitutes and biological factors alone or combined with bone graft have shown conflicting results. Low level of evidence studies and high heterogeneity (χ² = 271.4, df = 72, p < 0.001; I² = 73.5%, τ² = 0.05) in data analysis could result in the risk of bias. Further high-quality studies would better clarify these results in the future.

The Effect of Tobacco Smoking on Adverse Events Following Adult Complex Deformity Surgery: Analysis of 270 Patients From the Prospective, Multicenter Scoli-RISK-1 Study

STUDY DESIGN

Post-hoc analysis of a prospective, multicenter cohort study.

OBJECTIVE

To analyze the impact of smoking on rates of postoperative adverse events (AEs) in patients undergoing high-risk adult spine deformity surgery.

SUMMARY OF BACKGROUND DATA

Smoking is a known predictor of medical complications after adult deformity surgery, but the effect on complications, implant failure and other AEs has not been adequately described in prospective studies.

METHODS

Twenty-six patients with a history of current smoking were identified out of the 272 patients enrolled in the SCOLI-RISK-1 study who underwent complex adult spinal deformity surgery at 15 centers, with 2-year follow-up. The outcomes and incidence of AEs in these patients were compared to the nonsmoking cohort (n = 244) using univariate analysis, with additional multivariate regression to adjust for the effect of patient demographics, complexity of surgery, and other confounders.

RESULTS

The number of levels and complexity of surgery in both cohorts were comparable. In the univariate analysis, the rates of implant failure were almost double (odds ratio 2.28 [0.75-6.18]) in smoking group (n = 7; 26.9%)) that observed in the nonsmoking group (n = 34; 13.9%), but this was not statistically significant (P = 0.088). Surgery-related excessive bleeding (>4 L) was significantly higher in the smoking group (n = 5 vs. n = 9; 19.2% vs. 3.7%; OR 6.22[1.48 - 22.75]; P = 0.006). Wound infection rates and respiratory complications were similar in both groups. In the multivariate analysis, the smoking group demonstrated a higher incidence of any surgery-related AEs over 2 years (n = 13 vs. n = 95; 50.0% vs. 38.9%; OR 2.12 [0.88-5.09]) (P = 0.094).

CONCLUSION

In this secondary analysis of patients from the SCOLI-RISK-1 study, a history of smoking significantly increased the risk of excessive intraoperative bleeding and nonsignificantly increased the rate of implant failure or surgery-related AEs over 2 years. The authors therefore advocate a smoking cessation program in patients undergoing complex adult spine deformity surgery.

LEVEL OF EVIDENCE

2.

Preoperative Maximization to Reduce Complications in Spinal Surgery

STUDY DESIGN

Invited narrative review.

OBJECTIVES

The aim of this review was to summarize current literature regarding risk factors that surgeons can optimize in the preoperative setting in the spinal surgery patient, in order to reduce complications and improve patient-reported outcomes.

METHODS

Review of the relevant literature by the authors.

RESULTS

Modifiable risk factors identified relative to the patient include obesity, malnutrition/nutrient deficiency, diabetes/hyperglycemia, preoperative anemia, vitamin D/DEXA (dual-energy radiograph absorptiometry), nicotine use/smoking, and opioid use/psychosocial factors.

CONCLUSION

By maximizing a patient's physiological and psychological status prior to elective spine surgery, we may move closer to achieving the goals of value-based care: improving patient-reported outcomes while decreasing the cost of care.

Effect of Trabecular Microstructure of Spinous Process on Spinal Fusion and Clinical Outcomes After Posterior Lumbar Interbody Fusion: Bone Surface/Total Volume as Independent Favorable Indicator for Fusion Success

OBJECTIVE

We assessed the trabecular microarchitecture of the spinous process as an autograft and investigated its correlations with fusion success and clinical outcomes for patients undergoing posterior lumbar interbody fusion.

METHODS

Micro-computed tomography reconstruction techniques were used to scan cancellous bone specimens from spinous processes. We then measured the microarchitectural parameters for 105 subjects.

RESULTS

The patient cohort included 44 older men and 61 postmenopausal women with a minimum of 2-year follow-up data available. The complete fusion rate was 87.6% (92 of 105) at the last follow-up. When stratified by fusion status, the union group had significantly greater bone surface/total volume (BS/TV) and trabecular number but significantly lower trabecular separation than the nonunion group. No statistically significant differences were observed between the 2 groups in the clinical variables, except for the bone mineral density at the femoral neck (P = 0.028). On binomial logistic regression analysis, BS/TV was identified as an independent predictor for fusion success (odds ratio, 8.532; P = 0.032). The receiver operating characteristic curve showed that BS/TV had excellent performance in predicting successful fusion (area under the curve, 0.807). Using a cutoff value for BS/TV of 3.145, a greater BS/TV was significantly associated with visual analog scale scores for lower back pain 6 months postoperatively and lower Oswestry disability index scores at 12 and 24 months postoperatively but not with visual analog scale scores for leg pain.

CONCLUSIONS

Our data suggest that microstructural deterioration of the spinal process as an autograft has detrimental effects on spinal fusion and clinical outcomes for patients undergoing instrumented posterior lumbar interbody fusion. Specifically, the microstructural parameter BS/TV has good potential for assessing lumbar bone quality and predicting fusion success.

The Effect of Tobacco Use on Postoperative Pain Following Anterior Cervical Discectomy and Fusion

STUDY DESIGN

This was a retrospective cohort study.

OBJECTIVE

To identify the differences in inpatient pain scores, narcotic consumption, and patient-reported outcomes (PROs) between tobacco users and nonusers following an anterior cervical discectomy and fusion (ACDF).

SUMMARY OF BACKGROUND DATA

Previous studies have investigated tobacco use as a risk factor for negative postsurgical outcomes following spine surgery; however, few studies have analyzed the effects of tobacco on pain following ACDF.

METHODS

Patients undergoing primary, 1-level, or 2-level ACDF were retrospectively reviewed and stratified by tobacco use at the time of surgery. Inpatient pain scores and narcotic consumption were collected. Neck Disability Index and Visual Analogue Scale (VAS) neck and arm pain scores were collected preoperatively and at 6-week, 3-month, and 6-month follow-up visits. Differences in demographics and perioperative characteristics were assessed using χ analysis and multivariate linear regression. An association between immediate postoperative pain, narcotics consumption, and long-term PROs was tested for using multivariate linear regression.

RESULTS

A total of 192 patients were included and stratified by tobacco use: tobacco (n=25) and nontobacco (n=167). There were no significant differences in demographic and perioperative characteristics. No statistical differences were observed in inpatient VAS pain scores and narcotic consumption on postoperative day 0 and postoperative day 1. Preoperative VAS neck pain and arm pain was greater in tobacco users, however, improvements in neck and arm pain were similar in the postoperative period through 6-month follow-up. In addition, no statistical differences in Neck Disability Index were observed preoperatively or at any postoperative time points.

CONCLUSIONS

Our study suggests that tobacco use does not influence inpatient pain scores, narcotic consumption, and improvements in PROs following ACDF. As such, tobacco users and nonusers should receive similar postoperative pain management protocols following surgery.

LEVEL OF EVIDENCE

Level III.

Effects of smoking on cervical disc arthroplasty

Objective

Cigarette smoking can adversely affect bone fusion in patients who undergo anterior cervical discectomy and fusion. However, there is a paucity of data on smoking among patients who have undergone cervical disc arthroplasty (CDA). The present study aimed to compare the clinical and radiological outcomes of smokers to those of nonsmokers following CDA.

Methods

The authors retrospectively reviewed the records of consecutive patients who had undergone 1- or 2-level CDA for cervical disc herniation or spondylosis and had a minimum 2-year follow-up. All patients were grouped into a smoking group, which consisted of those who had consumed cigarettes within 6 months prior to the CDA surgery, or a nonsmoking group, which consisted of those who had not consumed cigarettes at all or within 6 months of the CDA. Clinical outcomes were evaluated according to the visual analog scale for neck and arm pain, Neck Disability Index, Japanese Orthopaedic Association Scale, and Nurick Scale at each time point of evaluation. Radiological outcomes were assessed using radiographs and CT for multiple parameters, including segmental range of motion (ROM), neutral lordotic curve, and presence of heterotopic ossification (HO).

Results

A total of 109 patients completed at least 2 years of follow-up and were analyzed (mean follow-up 42.3 months). There were 89 patients in the nonsmoking group and 20 in the smoking group. The latter group was younger and predominantly male (both p < 0.05) compared to the nonsmoking group. The two groups had similar improvements in all clinical outcomes after CDA compared to preoperatively. Radiological evaluations were also very similar between the two groups, except for two factors. The smoking group had well-preserved segmental ROM after CDA at an average of 8.1° (both pre- and postoperation). However, while the nonsmoking group remained mobile, segmental ROM decreased significantly (8.2° to 6.9°, p < 0.05) after CDA. There was a trend toward more HO development in the nonsmoking group than in the smoking group, but the difference was without significance (59.6% vs 50.0%, p = 0.43).

Conclusions

During an average 3.5 years of follow-up after 1- and 2-level CDA, cigarette smokers and nonsmokers had similar improvements in clinical outcomes. Moreover, segmental mobility was slightly better preserved in smokers. Since smoking status did not negatively impact outcomes, CDA may be a reasonable option for selected patients who have smoked.

Abbreviations

ACDF = anterior cervical discectomy and fusion; ASD = adjacent-segment degeneration; CDA = cervical disc arthroplasty; FDA = Food and Drug Administration; HO = heterotopic ossification; JOA = Japanese Orthopaedic Association; NDI = Neck Disability Index; ROM = range of motion; VAS = visual analog scale.

Deep flexor sarcopenia as a predictor of poor functional outcome after anterior cervical discectomy in patients with myelopathy

BACKGROUND

Paraspinal muscle morphometry has been recognized to be a prognostic factor across various surgical conditions, but its utility in predicting disease-specific outcomes in spine surgery remains under-explored.

METHODS

A prospective cohort study was performed on 45 consecutive patients undergoing anterior cervical discectomy (ACD) for single-level, symptomatic cervical degenerative disc disease causing radiculomyelopathy or myelopathy. Previously described predictors of outcome such as age, gender, smoking, comorbidities, duration of symptoms, preoperative Nurick grade, extent of cord compression, and signal intensity change in the cord were recorded. Additionally, MRI-based morphometrics of the superficial and deep paraspinal muscles were recorded. Logistic regression (LR) analysis was performed using a purposeful variable selection process to identify variables that independently predicted Nurick grade improvement (NGI).

RESULTS

At a mean follow-up of 20.02 ± 8.63 months after ACD, 37 (82.22%) patients demonstrated NGI. LR analysis yielded three predictors of NGI of which two were related to the deep flexor muscles. While a worse preoperative Nurick grade negatively predicted NGI, a deep flexor area and deep flexor/deep extensor area ratio positively predicted NGI. The regression model demonstrated a good fit and was statistically significant (χ²(3) = 22.18, p < 0.0001). The model explained 64% of the variance in NGI and correctly classified 89% of cases.

CONCLUSIONS

This study has for the first time identified the utility of paraspinal morphometrics in predicting disease-specific functional outcome after cervical spine surgery. Our results indicate that in addition to preoperative Nurick grade, an already accepted outcome predictor, the deep flexor cross-sectional area, and the deep flexor/deep extensor ratio are strong predictors of NGI following ACD for single-level, symptomatic cervical degenerative disc disease with myelopathy. Deep muscle morphometrics could be included in future risk stratification algorithms for patients with cervical disc disease.

The Role of Potentially Modifiable Factors in a Standard Work Protocol to Decrease Complications in Adult Spinal Deformity Surgery: A Systematic Review, Part 1

STUDY DESIGN

Structured Literature Review.

OBJECTIVES

We sought to evaluate the peer-reviewed literature for potentially modifiable patient and surgical factors that could be incorporated into a Standard Work protocol to decrease complications in adult spinal deformity (ASD) surgery.

SUMMARY OF BACKGROUND DATA

Lean Methodology uses Standard Work to improve efficiency and decrease waste and error. ASD is known to have a high surgical complication rate. Several patient and surgical potentially modifiable factors have been suggested to affect complications, including preoperative hemoglobin, bone density, body mass index (BMI), age-appropriate realignment, preoperative albumin/prealbumin, and smoking status. We sought to evaluate the literature for evidence supporting these factors to include in a Standard Work protocol to decrease complications.

METHODS

Each of these six factors was developed into an appropriate clinical question that included the patient population, surgical intervention, a comparison group, and outcomes measure (PICO question). A comprehensive literature search was then performed. The authors reviewed abstracts and analyzed data from included studies. From 456 initial citations with abstract, 173 articles underwent full-text review. The best available evidence for clinical questions regarding the influence of these factors was provided by 93 included studies.

RESULTS

We found fair evidence supporting a low preoperative hemoglobin level associated with increased transfusion rates and decreased BMD and increased BMI associated with increased complication rates. Fair evidence supported low albumin/prealbumin associated with increased complications. There was fair evidence associating smoking exposure to increased reoperations, but conflicting evidence associating it with increased complications. There was no evidence in the literature evaluating age-appropriate realignment and complications.

CONCLUSION

Preoperative hemoglobin, bone density, body mass index, preoperative albumin/prealbumin, and smoking status all are potentially modifiable risk factors that are associated with increased complications in the adult spine surgery population. Developing a Standard Work Protocol for patient evaluation and optimization should include these factors.

LEVEL OF EVIDENCE

Level II.

Minimally Effective Dose of Bone Morphogenetic Protein in Minimally Invasive Lumbar Interbody Fusions: Six Hundred Ninety Patients in a Dose-Finding Longitudinal Cohort Study

STUDY DESIGN

Retrospective longitudinal cohort.

OBJECTIVE

We sought to demonstrate the minimally effective bone morphogenetic protein (BMP) dose to achieve fusion in minimally invasive transforaminal lumbar interbody fusions.

SUMMARY OF BACKGROUND DATA

Multiple studies have been conducted, which used a wide range of BMP doses for lumbar fusions highlighting associated risks and benefits. There is, however, a paucity in the literature in determining the minimally effective dose.

METHODS

Consecutive patients who underwent transforaminal lumbar interbody fusion from 2009 to 2014 were reviewed. Fusion was determined by a combination of computed tomography and dynamic x-ray by independent radiologists. We used backward stepwise multiple logistic regression with fusion as the dependent variable to determine whether BMP dose/level was a significant predictor for fusion. To determine the minimally effective dose of BMP/level, separate logistic regressions for different BMP dose ranges and sensitivity analyses were used. A P value ≤0.025 was considered significant.

RESULTS

There were 1102 interspaces among 690 patients. Average BMP dose was 1.28 mg/level. Overall fusion was 95.2% with a mean follow-up of 19 months. BMP dose/level was a significant predictor for fusion. Odds of fusion increased by 2.02 when BMP dose range was increased from (0.16-1 mg/level) to (1.0-2 mg/level), but fusion odds did not increase when BMP dose increased to more than 2 mg/level.

CONCLUSION

BMP dose/level was a significant predictor for fusion. There was a significant increase in odds of fusion when BMP dose increased from 0.16 to 1 mg/level to 1.0 to 2 mg/level. No benefit from increasing the dose more than 2 mg/level was found, suggesting 1.0 mg/level to be the minimally effective BMP dose.

LEVEL OF EVIDENCE

3.

Bone Graft Substitutes in Single- or Double-Level Anterior Cervical Discectomy and Fusion: A Systematic Review

STUDY DESIGN

Systematic review OBJECTIVE.: To undertake a systematic review of published literature to evaluate efficacy of bone graft substitutes on radiographic and clinical outcomes in single- or double-level anterior cervical discectomy and fusion (ACDF) for degenerative disease.

SUMMARY OF BACKGROUND DATA

ACDF is one of the most common spinal surgeries completed in the United States. Today bone graft substitutes including ceramic-based synthetic bone grafts, allografts, bone morphogenetic proteins (BMPs), mesenchymal stem cells, and bone marrow aspirate are widely used to enhance fusions; even though the efficacy of these substitutes is poorly defined. Critical evaluation of these products is necessary to optimize radiographic and clinical outcomes for ACDF in degenerative disease.

METHODS

A systematic literature review of 22 published articles was conducted. All articles reported results on patients who underwent a single- or double-level ACDF performed using a bone graft substitute and reported results on radiographic fusion rates at least 6 months after surgery.

RESULTS

All studies using BMP showed 100% fusion rate despite length of the study or whether additional bone graft substitutes were used. Use of only ceramic-based synthetics had the lowest fusion rate, 80.5%. Use of only mesenchymal stem cells resulted in an average fusion rate of 87.7%. When used alone, allograft resulted in an average fusion rate of 87.3%. This was significantly influenced by one outlier, Kim et al, which when removed, increased the fusion rate to 93.5%. Clinical outcomes were improved postoperatively irrespective of the graft used, although dysphagia was significantly greater in studies using BMP (P < 0.001).

CONCLUSION

Allograft alone has the lowest cost with similar fusion rates and clinical outcomes compared to other bone graft substitutes. Physicians should consider this when choosing to use bone graft substitutes for routine ACDFs.

LEVEL OF EVIDENCE

4.

Reconsidering the minimally important difference: evidence of instability over time and across groups

BACKGROUND CONTEXT

Underlying cognitive factors have been found to influence patients' symptom experience. Current evidence suggests that concomitant changes in appraisal must be taken into account to accurately interpret change as measured by standard spine patient-reported outcomes (PROs).

PURPOSE

To investigate changes in patients' minimally important differences (MID) over recovery from spinal surgery; whether and how cognitive appraisal processes are implicated in the change trajectories.

STUDY DESIGN/SETTING

Longitudinal cohort study with up to 12 months follow-up.

PATIENT SAMPLE

Surgical patients (n = 167) with a diagnosis of disc herniation or spinal stenosis.

OUTCOME MEASURES

Standard spine patient-reported PROs were used (Rand-36, Oswestry Disability Index, Numerical Rating Scale for pain, PROMIS Pain Impact).

METHODS

This study was funded by the Feldberg Chair in Spinal Research, Sunnybrook Health Sciences Centre and the authors have no conflicts of interest. MID used an anchor technique and was computed by global assessment of change (GAC) grouping. Participants were binned into groups based on their GAC response patterns at all time points: Consistently better post-surgery, consistently worse post-surgery, and bouncers, whose GAC ratings fluctuate (ie, better-then-worse-then-better; or vice versa). Individuals' longitudinal quality of life (QOL) and appraisal slope scores were computed. QOL-appraisal slopes' correlations were computed by GAC group. Fisher's Z transformation tested the hypothesis that GAC groups differed in the QOL-appraisal relationship over time.

RESULTS

Moderate to large changes are recognized as clinically important in the early stages of recovery (ie, 6 weeks post-surgery), and over time smaller and smaller changes become important. The three pattern groups emphasized and deemphasized different standards of comparison over time, with the Better group emphasizing personal goals and the Worse and Bouncers deemphasizing doctors' input. These group differences translated to differential relationships between PRO change and appraisal changes over time.

CONCLUSIONS

The MID reflects increasingly subtle change over time in PROs. Appraisal may influence how patients experience the same (MID) change over time, with better outcomes associated with emphasizing long-term goals. PRO change seems to be driven by different standards of comparison. Potential avenues for clinical intervention are discussed.

Evaluation of an increased strut porosity silicate-substituted calcium phosphate, SiCaP EP, as a synthetic bone graft substitute in spinal fusion surgery: a prospective, open-label study

Purpose

Silicate-substituted calcium phosphate-enhanced porosity (SiCaP EP, Inductigraft™, Altapore) is a synthetic bone graft material with enhanced strut porosity of 31–47%. SiCaP EP remains to be fully clinically evaluated in patients undergoing instrumented posterolateral fusion (PLF) surgery. We conducted a prospective, open-label, non-randomised, multicentre clinical study to evaluate efficacy of SiCaP EP as bone grafting material in PLF surgery with instrumentation for treatment of spinal disorders.

Methods

Patients with degenerative disc disease, spondylolisthesis or spinal stenosis underwent PLF surgery with SiCaP EP. The primary endpoint was evaluated in the per protocol population (N = 102) as solid fusion at postoperative month 12 assessed using computed tomography scans, with motion assessed using flexion–extension radiographs. Clinical outcomes included the Oswestry Disability Index, 36-item short-form health survey for quality-of-life, visual analog scale for pain scores and neurological assessments. Adverse events were recorded.

Results

Successful fusion was achieved in 59/89 (66.3%) patients at month 6, 88/102 patients (86.3%) at month 12 (primary endpoint) and 87/96 (90.6%) patients at month 24. Disability and pain reduced following surgery. Quality-of-life improved and neurological function was maintained postoperatively. Forty-three (33.3%) of the 129 patients who underwent surgery experienced adverse events; back pain was most frequent (n = 10); nine and 14 patients experienced serious adverse events judged related to device and procedure, respectively.

Conclusions

Enhanced strut porosity SiCaP EP provided high (month 12: 86.3%) spinal fusion success rates in PLF surgery. Fusion success was associated with improved clinical outcomes in patients within 12 months, relative to baseline.

ClinicalTrials.gov identifier

NCT01452022

Graphical abstract

These slides can be retrieved under Electronic Supplementary Material.