Surgeon Experience Matters: An Exact Matched Analysis of TLIF Outcomes Demonstrates No Difference in Surgical Outcomes Between Experienced Neurosurgeons and Orthopedic Surgeons

STUDY DESIGN

Retrospective cohort study.

OBJECTIVE

To compare surgical and medical complications profile between neurosurgeons and orthopedic surgeons after transforaminal lumbar interbody fusion (TLIF) procedures.

BACKGROUND

Studies comparing the impact of spine surgeon specialty (neurosurgery vs. orthopedic spine) on TLIF outcomes have been inconclusive and failed to control for operative learning curves and surgical maturity. Orthopedic spine surgeons perform fewer spine procedures in residency, although these differences may be attenuated by mandatory fellowship before starting practice. Any observed differences are likely attenuated with increasing surgeon experience.

MATERIALS AND METHODS

Using an all-payer claims database, PearlDiver Mariner, 120 million patient records were analyzed between 2010 and 2022, to identify individuals with lumbar stenosis or spondylolisthesis who underwent index one- to three-level TLIF procedures. International Classification of Diseases-Ninth Edition (ICD-9), International Classification of Diseases-10th Edition (ICD-10) and Current Procedural Terminology (CPT) codes were used to query the database. Only Neurosurgeons and Orthopedic spine surgeons who had performed at least 250 procedures were included in the study. Patients undergoing surgery for tumor, trauma, or infection were excluded. 1:1 exact matching was performed using demographic factors, medical comorbidities, and surgical factors which were significantly associated with all-cause surgical or medical complications in a linear regression model.

RESULTS

1:1 exact matching created two equal groups of 18,195 patients without baseline differences who underwent TLIF procedures by neurosurgeons or orthopedic surgeons. There was no difference in all-cause surgical complications between neurosurgeons and orthopedic spine surgeons (relative risk=1.008, 95% CI: 0.850-1.195, P =0.965). All-cause medical complication rate was higher in the neurosurgery cohort (relative risk=1.144, 95% CI: 1.042-1.258, P =0.005).

CONCLUSION

The results of this study suggest that after accounting for surgical maturity, neurosurgeons and orthopedic spine surgeons have similar surgical outcomes. However, neurosurgeons have higher all-cause medical complication rates compared with orthopedic spine surgeons. Further research is warranted to validate this relationship in other spine procedures and for other outcomes.

Synthetic Interbody Devices and Traditional Bone Graft Are Associated With a Similar Rate of Surgical Complications After 1-2 Level Anterior Cervical Discectomy and Fusions

STUDY DESIGN

Retrospective cohort.

OBJECTIVE

To compare the rates of all-cause surgical complications of synthetic interbody devices versus allograft or autograft in patients undergoing 1-2 levels anterior cervical discectomy and fusion (ACDF) procedures.

SUMMARY OF BACKGROUND DATA

Cervical degenerative disorders affect up to 60% of older adults in the United States. Both traditional allograft or autograft and synthetic interbody devices (polyetheretherketone or titanium) are used for decompression and arthrodesis, with increasing utilization of the latter. However, the differences in their postsurgical complication profiles are not well-characterized.

PATIENTS AND METHODS

Patients who underwent 1-2 level ACDFs for cervical radiculopathy or myelopathy between 2010 and 2022 were identified using the PearlDiver Mariner all-claims insurance database. Patients undergoing surgery for nondegenerative pathologies, such as tumors, trauma, or infection, were excluded. 1:1 exact matching was performed based on factors that were significant predictors of all-cause surgical complications in a linear regression model. The primary outcome measure was the development of all-cause surgical complications after 1-2 level ACDFs. The secondary outcome was all-cause medical complications.

RESULTS

1:1 exact matching resulted in two equal groups of 11,430 patients who received treatment with synthetic interbody devices or allograft/autograft. No statistically significant difference in all-cause surgical complications was found between the synthetic cohort and the allograft or autograft cohort after 1-2 level ACDFs (Relative Risk: 0.86, 95% confidence interval: 0.730-1.014, P = 0.079). No significant differences were observed regarding any specific surgical complications except for pseudoarthrosis (Relative Risk: 0.73, 95% confidence interval: 0.554-0.974, P = 0.037), which was higher in the allograft/autograft cohort.

CONCLUSION

After 1:1 exact matching to control for confounding variables, the findings of this study suggest that all-cause surgical complications are similar in patients undergoing ACDFs with synthetic interbody devices or allograft/autographs. However, the rate of pseudarthrosis appears to be higher in patients with allograft/autographs. Future prospective studies are needed to corroborate these findings.

Cannabis Use is Associated With Higher Rates of Pseudarthrosis Following TLIF: A Multi-Institutional Matched-Cohort Study

STUDY DESIGN

This was a retrospective cohort study.

OBJECTIVE

To compare the rates of pseudarthrosis in patients undergoing 1 to 3 level transforaminal lumbar interbody fusion (TLIF) procedures between cannabis users and noncannabis users.

SUMMARY OF BACKGROUND DATA

Recreational use of cannabis is common, though it remains poorly studied and legally ambiguous in the United States. Patients with back pain may turn to adjunctive use of cannabis to manage their pain. However, the implications of cannabis use on the achievement of bony fusion are not well-characterized.

METHODS

Patients who underwent 1 to 3 level TLIF for degenerative disc disease or degenerative spondylolisthesis between 2010 and 2022 were identified using the PearlDiver Mariner all-claims insurance database. Cannabis users were identified with ICD 10 code F12.90. Patients undergoing surgery for nondegenerative pathologies such as tumors, trauma, or infection were excluded. 1:1 exact matching was performed using demographic factors, medical comorbidities, and surgical factors which were significantly associated with pseudarthrosis in a linear regression model. The primary outcome measure was development of pseudarthrosis within 24 months after 1 to 3 level TLIF. The secondary outcomes were the development of all-cause surgical complications as well as all-cause medical complications.

RESULTS

A 1:1 exact matching resulted in two equal groups of 1593 patients who did or did not use cannabis and underwent 1 to 3 level TLIF. Patients who used cannabis were 80% more likely to experience pseudarthrosis compared with patients who do not [relative risk (RR): 1.816, 95% CI: 1.291-2.556, P <0.001]. Similarly, cannabis use was associated with significantly higher rates of all-cause surgical complications (RR: 2.350, 95% CI: 1.399-3.947, P =0.001) and all-cause medical complications (RR: 1.934, 95% CI: 1.516-2.467, P <0.001).

CONCLUSION

After 1:1 exact matching to control for confounding variables, the findings of this study suggest that cannabis use is associated with higher rates of pseudarthrosis, as well as higher rates of all-cause surgical and all-cause medical complications. Further studies are needed to corroborate our findings.

Ehlers-Danlos Syndrome is Associated with Increased Rates of Adjacent Segment Disease Following TLIF: A Propensity Matched Study

BACKGROUND

Ehlers-Danlos syndrome (EDS) is a collection of connective tissue disorders which are often associated with tissue laxity and disc degeneration. However, the implications of EDS on the risk of adjacent segment disease (ASD) after transforaminal lumbar interbody fusion (TLIF) are not well described. The objective of this study is to compare the rates of ASD among patients with EDS and those without EDS.

METHODS

Patients who underwent 1-3 level TLIF for degenerative disc disease between 2010-2022 were identified using the PearlDiver Mariner all-claims insurance database. Patients with all types of EDS were included. Patients undergoing surgery for tumors, trauma, or infection were excluded. 1:1 propensity matching was performed using demographic factors, medical comorbidities, and surgical factors which were significantly associated with ASD in a linear regression model. The primary outcome measure was the development of ASD. The secondary outcomes were the development of pseudoarthrosis, medical complications, and surgical complications.

RESULTS

Propensity matching resulted in 2 equal groups of 85 patients who did or did not have EDS and underwent 1-3 level TLIF. Patients without EDS were less likely to experience ASD (RR 0.18, 95% CI 0.09-0.35, P < 0.001). There was no significant difference between the 2 patient groups with regards to a diagnosis of pseudoarthrosis, and there was no significant difference for all-cause medical and surgical complications between the 2 patient groups.

CONCLUSIONS

After propensity matching to control for confounding variables, the findings of this study suggest that EDS may be associated with an increased risk of ASD following TLIF. Future studies are needed to corroborate these findings.

Correlation Between Rod Fracture and Shear Stress: A Novel Parameter

BACKGROUND

We sought to assess the accuracy of a novel parameter proportional to the rod shear stress (RSS) in identifying patients at risk of rod fracture (RF) after surgery for correction of adult spinal deformity.

METHODS

We performed a retrospective medical record review of patients aged ≥18 years treated for adult spinal deformity between 2004 and 2014 with ≥24 months of follow-up. The primary outcome was RFs identified radiographically. Patient weight (w), number of instrumented levels (N), and minimum rod diameter (d) were recorded and used to calculate the RSS parameter (RSS=Nwd2). Receiver operating characteristic curves were produced and the area under the curve (AUC ± 95% confidence interval [CI]) was calculated to compare this parameter's discriminative accuracy to that of its constituent variables. The sensitivity, specificity, and likelihood ratios (LRs) were calculated.

RESULTS

A total of 28 RF-positive and 154 RF-negative patients were included. The average age was 59.2 ± 9.6 years, and 93.4% were women. The RSS parameter produced the greatest AUC (0.73 ± 0.11). At an RSS cutoff of 30.1, it achieved a sensitivity of 71.4% and specificity of 71.4% (LR, 2.5; 95% CI, 1.8-3.5). The number of instrumented levels produced the next-greatest AUC (0.65 ± 0.12), with a sensitivity of 78.6% and specificity of 50.0% at a cutoff of 15 (LR, 1.6; 95% CI, 1.2-2.0).

CONCLUSIONS

The RSS is calculated using easily obtainable information and shows potential as a tool for predicting patient-specific risk of RF after spinal fusion. The number of instrumented levels also correlates strongly with the occurrence of RFs and is not significantly less accurate than the RSS. A larger sample size and prospective validation would be useful in determining with greater confidence which parameter is superior for predicting RFs after spinal fusion.

Translating Animal Models of Ischemic Stroke to the Human Condition

Ischemic stroke is a leading cause of death and disability. However, very few neuroprotective agents have shown promise for treatment of ischemic stroke in clinical trials, despite showing efficacy in many successful preclinical studies. This may be attributed, at least in part, to the incongruency between experimental animal stroke models used in preclinical studies and the manifestation of ischemic stroke in humans. Most often the human population selected for clinical trials are more diverse than the experimental model used in a preclinical study. For successful translation, it is critical to develop clinical trial designs that match the experimental animal model used in the preclinical study. This review aims to provide a comprehensive summary of commonly used animal models with clear correlates between rodent models used to study ischemic stroke and the clinical stroke pathologies with which they most closely align. By improving the correlation between preclinical studies and clinical trials, new neuroprotective agents and stroke therapies may be more accurately and efficiently identified.

TLIF is Associated With Lower Rates of Adjacent Segment Disease and Complications Compared to ALIF: A Matched-Cohort Analysis

STUDY DESIGN

Retrospective cohort.

OBJECTIVE

To compare the rate of adjacent segment disease (ASD) in patients undergoing anterior lumbar interbody fusion (ALIF) versus transforaminal lumbar interbody fusion (TLIF) for the treatment of degenerative stenosis and spondylolisthesis.

SUMMARY OF BACKGROUND DATA

ALIF and TLIF are frequently used to treat Lumbar stenosis and spondylolisthesis. While both approaches have distinct advantages, it is unclear whether there are any differences in rates of ASD and postoperative complications.

METHODS

A retrospective cohort study of patients who underwent index 1-3 levels ALIF or TLIF between 2010 and 2022, using the PearlDiver Mariner Database, an all-claims insurance database (120 million patients). Patients with a history of prior lumbar surgery and those undergoing surgery for cancer, trauma, or infection were excluded. Exact 1:1 matching was performed using demographic factors, medical comorbidities, and surgical factors found to be significantly associated with ASD in a linear regression model. The primary outcome was a new diagnosis of ASD within 36 months of index surgery, and secondary outcomes were all-cause medical and surgical complications.

RESULTS

Exact 1:1 matching resulted in 2 equal groups of 106,451 patients undergoing TLIF and ALIF. The TLIF approach was associated with a lower risk of ASD (RR 0.58, 95% CI 0.56-0.59, P < 0.001) and all-cause medical complications (RR 0.94, 95% CI 0.91-0.98, P =0.002). All-cause surgical complications were not significantly different between both groups.

CONCLUSION

After 1:1 exact matching to control for confounding variables, this study suggests that for patients with symptomatic degenerative stenosis and spondylolisthesis, a TLIF procedure (compared to ALIF) is associated with a decreased risk of developing ASD within 36 months of index surgery. Future prospective studies are needed to corroborate these findings.

LEVEL OF EVIDENCE

Level-3.

No Difference in Surgical Outcomes between Stand-Alone Devices and Anterior Plating for 1-2 level Anterior Cervical Discectomy and Fusion: A 1:1 Exact Matched Analysis

STUDY DESIGN

Retrospective cohort.

OBJECTIVE

Compare rates of all-cause surgical and medical complications between zero-profile (stand-alone) implants versus any graft type with anterior plate in patients undergoing 1-2 level anterior cervical discectomy and fusion (ACDF) for treatment of degenerative cervical myeloradiculopathy.

SUMMARY OF BACKGROUND DATA

Degenerative cervical myeloradiculopathy is increasingly prevalent in older adults. ACDF is a common surgical procedure for decompression of neural structures and stabilization and has been shown to have excellent outcomes. While ACDFs performed with a graft and plate has been the gold standard, more recently, zero-profile implants were developed to decrease implant related complications, such as severe postoperative dysphagia. However, there is a paucity of papers comparing the surgical and medical complications profile of zero-profile (stand-alone) implants to grafts with plating systems.

METHODS

Data was extracted from the PearlDiver Mariner Database using CPT codes to classify patients into 1-level, 2-levels, and total 1-2 level ACDFs. Patients undergoing surgery for non-degenerative pathologies such as tumors, trauma, or infection were excluded.

RESULTS

1:1 exact matching created two equal groups of 7,284 patients that underwent 1-2 level ACDF with either grafting with a plate or zero-profile (standalone) implant. There were no statistically significant difference in all-cause surgical complications, pseudarthrosis rate, dysphagia or need for revision surgery between both cohorts (RR 0.99, 95% CI 0.80-1.21, P = 0.95). Additionally, all-cause medical complications were similar between both cohorts (RR 1.07, 95% CI 0.862-1.330, P = 0.573) or any specific surgical or medical complication included in this study.

CONCLUSION

After 1:1 exact matching, the results of this study suggest that zero-profile (stand-alone) implants have similar outcomes compared to grafts with plating systems, with no observed differences in all-cause surgical or medical complications profile.

Toward global availability of low-cost, patient-specific cranial implants: creation and validation of automated CranialRebuild freeware application

PURPOSE

Financial restrictions limit the options for hermetically precise, patient-specific cranial implants (PSCIs) after decompressive hemicraniectomy (DHC) in low-income countries. Use of image segmentation, modeling software, and 3D printers has lowered costs associated with PSCIs. However, requirements of time and technical expertise have prevented widespread utilization. Our objective was to create a fully automated software algorithm that is able to generate a virtual model (.STL) of a negative of an implant using CT imaging following DHC.

METHODS

A freeware algorithm (CranialRebuild) was constructed with the following capabilities: (1) after the upload of digital imaging and communications in medicine files, the normal side is analyzed in reference to the side of DHC, (2) Boolean subtraction is used to obtain a virtual image of the desired implant, and (3) a two-piece virtual model (.STL) of the PSCI mold is generated. In four cadaveric specimens, a standard DHC was performed. Post-DHC CT imaging was used to obtain a .STL of the negative of the implant, which was then printed using poly-lactic acid (PLA). Methylmethacrylate cement was used to generate a PSCI from the mold. The PSCIs were implanted into the index specimens; cosmesis was subjectively evaluated using a 5-point Likert scale.

RESULTS

Two specimens were graded as 4/5, indicating that minor post-processing modification was needed for optimal cosmesis. Two specimens were graded as 3/5, indicating that optimal cosmesis could be obtained following moderate post-processing modification.

CONCLUSIONS

CranialRebuild can be used to create hermetically precise PSCIs at a fraction of the price of third-party vendors. Validation of this technology has significant implications for the accessibility of customized cranial implants worldwide.

Do Obese Patients Lose Weight After Lumbar Spine Surgery: A Systematic Review and Meta-Analysis

OBJECTIVE

Obesity is a major health care concern in the United States and is associated with high rates of postoperative complications after spine surgery. Obese patients assert that weight reduction is not possible unless spine surgery first relieves their pain and concomitant immobility. We describe the post-spine surgery effects on patient weight, with an emphasis on obesity.

METHODS

PubMed, EMBASE, Scopus, Web of Science, and Cochrane databases were systematically searched according to the PRISMA guidelines. The search included indexed terms and text words from database inception to the date of the search (15 April 2022). Studies chosen for inclusion had to have data reporting on pre- and postoperative patient weight after spine surgery. Data and estimates were pooled using the Mantel-Haenszel method for random-effects meta-analysis.

RESULTS

Eight articles encompassing 7 retrospective and 1 prospective cohort were identified. A random effects model analysis demonstrated that overweight and obese patients (body mass index [BMI], >25 kg/m2) had increased odds of clinically significant weight loss after lumbar spine surgery compared with non-obese patients (odds ratio, 1.63; 95% confidence interval, 1.43-1.86, P < 0.0001). There was no significant difference in the raw weight change between BMI categories (mean difference, -0.67 kg, 95% confidence interval, -4.71 to 3.37 kg, P = 0.7463).

CONCLUSIONS

Compared with non-obese patients (BMI, <25 kg/m2), overweight and obese patients have higher odds of clinically significant weight loss after lumbar spine surgery. No difference in pre-operative and post-operative weight was found, although statistical power was lacking in this analysis. Randomized controlled trials and additional prospective cohorts are needed to further validate these findings.

Bariatric Surgery Before Spine Surgery is Associated With Fewer Postsurgical Complications: A Systematic Review and Meta-Analysis

STUDY DESIGN

Systematic review and meta-analysis.

OBJECTIVE

To perform a systematic review and meta-analysis investigating the rate of adverse events after spine surgery in patients who underwent bariatric surgery (BS).

SUMMARY OF BACKGROUND DATA

Obesity is an established risk factor for postoperative complications after spine surgery. BS has been associated with improvements in health in patients with severe obesity. However, it is not known whether undergoing BS before spine surgery is associated with reduced adverse outcomes.

MATERIALS AND METHODS

PubMed, EMBASE, Scopus, and Web-of-Science were systematically searched according to "Preferred Reporting Items for Systematic Reviews and Meta-Analyses" guidelines. The search included indexed terms and text words from database inception to the date of the search (May 27, 2022). Data and estimates were pooled using the Mantel-Haenszel method for random-effects meta-analysis. Risk of bias was assessed using the Joanna Briggs Institute risk of bias tool. The primary outcome was an all-cause complication rate after surgery. Relative risks for surgical and medical complications were assessed.

RESULTS

A total of 4 studies comprising 177,273 patients were included. The pooled analysis demonstrated that the all-cause medical complication rate after spine surgery was lower in patients undergoing BS (relative risk: 0.54, 95% CI: 0.39, 0.74, P < 0.01). There was no difference in rates of surgical complications and 30-day hospital readmission rates between the cohort undergoing BS before spine surgery and the cohort that did not.

CONCLUSION

These analyses suggest that obese patients undergoing BS before spine surgery have significantly lower adverse event rates. Future prospective studies are needed to corroborate these findings.

LEVEL OF EVIDENCE

4.

Laminectomy With Fusion is Associated With Greater Functional Improvement Compared With Laminectomy Alone for the Treatment of Degenerative Lumbar Spondylolisthesis: A Systematic Review and Meta-Analysis

STUDY DESIGN

Systematic review and Meta-analysis.

OBJECTIVE

To compare outcomes and complications profile of laminectomy alone versus laminectomy and fusion for the treatment of degenerative lumbar spondylolisthesis (DLS).

SUMMARY OF BACKGROUND DATA

Degenerative lumbar spondylolisthesis is a common cause of back pain and functional impairment. DLS is associated with high monetary (up to $100 billion annually in the US) and nonmonetary societal and personal costs. While nonoperative management remains the first-line treatment for DLS, decompressive laminectomy with or without fusion is indicated for the treatment-resistant disease.

METHODS

We systematically searched PubMed and EMBASE for RCTs and cohort studies from inception through April 14, 2022. Data were pooled using random-effects meta-analysis. The risk of bias was assessed using the Joanna Briggs Institute risk of bias tool. We generated odds ratio and standard mean difference estimates for select parameters.

RESULTS

A total of 23 manuscripts were included (n=90,996 patients). Complication rates were higher in patients undergoing laminectomy and fusion compared with laminectomy alone (OR: 1.55, P <0.001). Rates of reoperation were similar between both groups (OR: 0.67, P =0.10). Laminectomy with fusion was associated with a longer duration of surgery (Standard Mean Difference: 2.60, P =0.04) and a longer hospital stay (2.16, P =0.01). Compared with laminectomy alone, the extent of functional improvement in pain and disability was superior in the laminectomy and fusion cohort. Laminectomy with fusion had a greater mean change in ODI (-0.38, P <0.01) compared with laminectomy alone. Laminectomy with fusion was associated with a greater mean change in NRS leg score (-0.11, P =0.04) and NRS back score (-0.45, P <0.01).

CONCLUSION

Compared with laminectomy alone, laminectomy with fusion is associated with greater postoperative improvement in pain and disability, albeit with a longer duration of surgery and hospital stay.

Preoperative HbA1c and Postoperative Outcomes in Spine Surgery: A Systematic Review and Meta-Analysis

STUDY DESIGN

Systematic review and meta-analysis.

OBJECTIVE

To perform a systematic review and meta-analysis of previous studies on HbA1c in preoperative risk stratification in patients undergoing spinal procedures and provide an overview of the consensus recommendations.

SUMMARY OF BACKGROUND DATA

Diabetes mellitus (DM) and hyperglycemia have been shown to be independent risk factors for increased surgical complications. Glycated Hemoglobin A1C (HbA1c), a surrogate for long term glycemic control, is an important preoperative parameter that may be optimized to reduce surgical complications and improve patient-reported outcomes. However, comprehensive systematic reviews on preoperative HbA1c and postoperative outcomes in spine surgery have been limited.

METHODS

We systematically searched PubMed, EMBASE, Scopus, and Web-of-Science for English-language studies from inception through April 5th, 2022, including references of eligible articles. The search was conducted according to PRISMA guidelines. Only studies in patients undergoing spine surgery with preoperative HbA1c values and postoperative outcomes available were included.

RESULTS

A total of 22 articles (18 retrospective cohort studies, 4 prospective observational studies) were identified with level of evidence III or greater. The majority of studies (n=17) found that elevated preoperative HbA1c was associated with inferior outcomes or increased risk of complications. Random-effect meta-analysis demonstrated that patients with preoperative HbA1c >8.0% had increased risk(s) of postoperative complications (RR: 1.85, 95% CI: [1.48, 2.31], P<0.01) and that patients with surgical site infection (SSI) had higher preoperative HbA1c (Mean Difference: 1.49%, 95% CI: [0.11, 2.88], P=0.03).

CONCLUSION

The findings of this study suggest that HbA1c >8.0% is associated with an increased risk of complications. HbA1c was higher by 1.49% on average among patients with SSI when compared to patients who did not experience SSI. These results suggest that elevated HbA1c is associated with less favorable outcomes following spine surgery.

LEVEL OF EVIDENCE

IV.

Lumbar Arthroplasty is Associated with a Lower Incidence of Adjacent Segment Disease Compared to ALIF: A Propensity Matched Analysis

STUDY DESIGN

Retrospective Cohort Study.

OBJECTIVE

To compare the rate of ASD between lumbar disc arthroplasty (LDA) and anterior lumbar interbody fusion (ALIF).

SUMMARY OF BACKGROUND DATA

Lumbar disc arthroplasty (LDA) and anterior lumbar interbody fusion (ALIF) are alternative surgical approaches used to treat lumbar degenerative disc disease. However, there is a paucity of studies comparing the risk of adjacent segment disease (ASD) following these procedures.

METHODS

Patients who underwent 1-2 level LDA or ALIF between 2010 and 2022 were identified in the PearlDiver Mariner insurance all-claims database. Exclusion criteria included history of prior lumbar spine surgery, or surgery for tumors, trauma, or infection. 1:1 propensity matching was performed using demographic factors, medical comorbidities, and surgical factors which were significantly associated with ASD.

RESULTS

1:1 Propensity matching created two equal groups of 1,625 patients without baseline differences who underwent LDA or ALIF. LDA was significantly associated with a lower risk of ASD (RR 0.932, 95% CI 0.899-0.967, P<0.001), and need for revision within 30 days (RR 0.235, 95% CI 0.079-0.698, P=0.007). There were no differences in all-cause surgical and medical complications between both groups.

CONCLUSION

After risk adjustment for demographic and clinical characteristics, the results suggest that LDA is associated with a lower risk of adjacent segment disease compared to ALIF. LDA was also associated with lower hospital cost and shorter length of stay.

Association between underlying autoimmune disease and small aneurysm size at rupture

OBJECTIVE

Although the role of inflammation in the development of aneurysms is established, less is known about the development of intracranial aneurysms in the setting of underlying autoimmune disease. The underlying systemic inflammatory characteristics of disorders such as systemic lupus erythematosus, rheumatoid arthritis, and Sjögren's syndrome may influence the development of intracranial aneurysms through common inflammatory pathways. The authors hypothesized that there is an association between underlying autoimmune disease and aneurysm growth and rupture.

METHODS

Medical records of patients who underwent cerebral angiography between August 2018 and August 2021 were manually reviewed. Autoimmune diseases as defined for this study are those known to have systemic inflammatory effects on the central nervous system or multiple other organ systems. Statistical analysis, including construction of multivariable linear and logistic regression models, was performed using R version 4.1.0.

RESULTS

Chart review identified 190 patients with 469 ruptured and unruptured saccular intracranial aneurysms. There were 31 patients with 44 aneurysms identified as having an autoimmune disease. The mean size of a ruptured aneurysm was significantly smaller among patients with autoimmune disease compared with patients without autoimmune disease (4.14 mm vs 5.34 mm, p = 0.03). The multivariate logistic regression model did not identify any significant association between rupture and autoimmune disease when controlling for other variables (p = 0.49). In the multivariate linear regression model, autoimmune disease was still significantly associated with a smaller size at rupture (p = 0.04), and smoking was associated with a larger size at rupture (p = 0.03) when controlling for other variables. A second multivariate logistic regression model found autoimmune disease to be independently associated with rupture at a size smaller than 7 mm (p = 0.02), while smoking was independently associated with rupture at a size larger than 7 mm (p = 0.01).

CONCLUSIONS

Autoimmune disease is associated with a smaller aneurysm size at rupture, although it is not associated with rupture itself. This association may be due to inflammatory pathways that are common to autoimmune diseases as well as aneurysm wall development. Although the authors were unable to identify any association between rupture status and the presence of autoimmune disease, the association between smaller size at rupture and autoimmune disease warrants further studies, as autoimmune disease may influence the trajectory of aneurysm development and the decision to treat.

Robotic and navigated pedicle screws are safer and more accurate than fluoroscopic freehand screws: a systematic review and meta-analysis

BACKGROUND CONTEXT

Navigated and robotic pedicle screw placement systems have been developed to improve the accuracy of screw placement. However, the literature comparing the safety and accuracy of robotic and navigated screw placement with fluoroscopic freehand screw placement in thoracolumbar spine surgery has been limited.

PURPOSE

To perform a systematic review and meta-analysis of randomized control trials that compared the accuracy and safety profiles of robotic and navigated pedicle screws with fluoroscopic freehand pedicle screws.

STUDY DESIGN/SETTING

Systematic review and meta-analysis PATIENT SAMPLE: Only randomized controlled trials comparing robotic-assisted or navigated pedicle screws placement with freehand pedicle screw placement in the thoracolumbar spine were included.

OUTCOME MEASURES

Odds ratio (OR) estimates for screw accuracy according to the Gertzbein-Robbins scale and relative risk (RR) for various surgical complications.

METHODS

We systematically searched PubMed and EMBASE for English-language studies from inception through April 7, 2022, including references of eligible articles. The search was conducted according to PRISMA guidelines. Two reviewers conducted a full abstraction of all data, and one reviewer verified accuracy. Information was extracted on study design, quality, bias, participants, and risk estimates. Data and estimates were pooled using the Mantel-Haenszel method for random-effects meta-analysis.

RESULTS

A total of 14 papers encompassing 12 randomized controlled trials were identified (n=892 patients, 4,046 screws). The pooled analysis demonstrated that robotic and navigated pedicle screw placement techniques were associated with higher odds of screw accuracy (OR 2.66, 95% CI 1.24-5.72, p=.01). Robotic and navigated screw placement was associated with a lower risk of facet joint violations (RR 0.09, 95% CI 0.02-0.38, p<.01) and major complications (RR 0.31, 95% CI 0.11-0.84, p=.02). There were no observed differences between groups in nerve root injury (RR 0.50, 95% CI 0.11-2.30, p=.37), or return to operating room for screw revision (RR 0.28, 95% CI 0.07-1.13, p=.07).

CONCLUSIONS

These estimates suggest that robotic and navigated screw placement techniques are associated with higher odds of screw accuracy and superior safety profile compared with fluoroscopic freehand techniques. Additional randomized controlled trials will be needed to further validate these findings.

C1 Lateral Mass Screw Placement Through Endonasal Corridor for Purpose of O-C1 Fusion: Morphometric Analysis in Cadaveric Specimens

BACKGROUND

Odontoidectomy may pose some risks for O-C1 and/or C1-C2 instability, with previous authors reporting techniques for endonasal C1-C2 fusion. However, no technique for endonasal O-C1 fusion currently exists. We sought to describe the feasibility of endonasal anterior C1 (AC1) screw placement for endonasal O-C1 fusion.

METHODS

Seven adult cadaveric heads were studied for endonasal placement of 14 C1 screws. Using thin-cut computed tomography (CT)-based "snapshot" neuronavigation assistance, 4 mm x 22 mm screws were placed in the C1 lateral mass using a 0° driver. Post-placement CT scans were obtained to determine site-of-entry measured from C1 anterior tubercle, screw angulation in axial and sagittal planes, and screw proximity to the central canal and foramen transversarium.

RESULTS

Average site-of-entry was 16.57 mm lateral, 2.23 mm rostral, and 5.53 mm deep to the anterior-most portion of the C1 ring. Average axial angulation was 19.49° lateral to midline, measured at the C1 level. Average sagittal angulation was 13.22° inferior to the palatal line, measured from the hard palate to the opisthion. Bicortical purchase was achieved in 11 screws (78.6%). Partial breach of the foramen transversarium was observed in 2 screws (14.3%), violation of the O-C1 joint space in 1 (7.1%), and violation of the central canal in 0 (0%). Average minimum screw distances from the unviolated foramen transversaria and central canal were 1.97 mm and 4.04 mm.

CONCLUSIONS

Navigation-assisted endonasal placement of AC1 screws is feasible. Additional studies should investigate the biomechanical stability of anterior C1 screw-plating systems, with anterior condylar screws as superior fixation point, compared to traditional posterior O-C1 fusion.

Noninvasive electrical stimulation as an adjunct to fusion procedures: a systematic review and meta-analysis

OBJECTIVE

Noninvasive electrical stimulation represents a distinct group of devices used to augment fusion rates. However, data regarding outcomes of noninvasive electrical stimulation have come from a small number of studies. The goal of this systematic review and meta-analysis was to determine outcomes of noninvasive electrical stimulation used as an adjunct to fusion procedures to improve rates of successful fusion.

METHODS

PubMed, Embase, and the Cochrane Clinical Trials database were searched according to search strategy and PRISMA guidelines. Random-effects meta-analyses of fusion rates with the three main modalities of noninvasive electrical stimulation, capacitively coupled stimulation (CCS), pulsed electromagnetic fields (PEMFs), and combined magnetic fields (CMFs), were conducted using R version 4.1.0 (The R Foundation for Statistical Computing). Both retrospective studies and clinical trials were included. Animal studies were excluded. Risk-of-bias analysis was performed with the Risk of Bias 2 (RoB 2) and Risk of Bias in Nonrandomized Studies of Interventions (ROBINS-I) tools.

RESULTS

Searches of PubMed, Embase, and the Cochrane Clinical Trials database identified 8 articles with 1216 participants meeting criteria from 213 initial results. There was a high overall risk of bias identified for the majority of randomized studies. No meta-analysis could be performed for CCS as only 1 study was identified. Meta-analysis of 6 studies of fusion rates in PEMF did not find any difference between treatment and control groups (OR 1.89, 95% CI 0.36-9.80, p = 0.449). Meta-analysis of 2 studies of CMF found no difference in fusion rates between control and treatment groups (OR 0.90, 95% CI 0.07-11.93, p = 0.939). Subgroup analysis of PEMF was limited given the small number of studies and patients, although significantly increased fusion rates were seen in some subgroups.

CONCLUSIONS

This meta-analysis of clinical outcomes and fusion rates in noninvasive electrical stimulation compared to no stimulation did not identify any increases in fusion rates for any modality. A high degree of heterogeneity between studies was noted. Although subgroup analysis identified significant differences in fusion rates in certain groups, these findings were based on a small number of studies and further research is needed. This analysis does not support routine use of these devices to augment fusion rates, although the data are limited by a high risk of bias and a small number of available studies.

An algorithm to improve lateralization accuracy of inferior petrosal sinus sampling: procedural nuances for complex patterns of venous drainage. Patient series

BACKGROUND

Inferior petrosal sinus sampling (IPSS) is a useful technique in the diagnosis of Cushing’s disease (CD) when the imaging finding is negative or equivocal. Different authors have reported considerable variability in the ability to determine tumor laterality with IPSS. Here the authors present a retrospective case series of 7 patients who underwent IPSS using a systematic algorithm to improve lateralization accuracy by identifying optimal sampling sites on the basis of individual cavernous sinus drainage patterns in each patient.

OBSERVATIONS

Of the 7 patients identified, 6 were determined to have CD and subsequently underwent surgery. IPSS was accurate in all patients from whom laterality was predicted. Arterial and venous angiography were used to define cavernous sinus drainage patterns and determine optimal sampling sites. All patients who underwent surgery achieved hormonal cure.

LESSONS

All IPSS predictions of lateralization were correct when available, and all patients who underwent surgery achieved hormonal cure. Advances in angiographic techniques for identification of the site of primary drainage from the cavernous sinus and subsequent optimization of microcatheter placement may improve the ability to predict tumor laterality.

The surgical history of head injury in motor vehicle collision

Motor vehicle collisions (MVCs) are a significant cause of head injuries today, but efforts to manage and prevent these injuries extend as far back as the beginning of modern neurosurgery itself. Head trauma in MVCs occurred as far back as 1899, and the surgical literature of the time mentions several cases of children being struck by passing automobiles. By the 1930s, Dr. Claire L. Straith, a Detroit plastic surgeon, recommended changes to automobile design after seeing facial injuries and depressed skull fractures that resulted from automobile accidents. During World War II, Sir Hugh Cairns, a British neurosurgeon, demonstrated the efficacy of motorcycle helmets in preventing serious head injury. In the 1950s, Dr. Frank H. Mayfield, a Cincinnati neurosurgeon on the trauma committee of the American College of Surgeons, made several recommendations, such as adding padded dashboards and seatbelts, to make automobiles safer. Ford implemented the recommendations from Dr. Mayfield and others into a safety package for the 1956 models. Significant work has also been done to prevent head injury in motorsports. Efforts by surgeons, especially neurosurgeons, to prevent head injury in MVCs have saved countless lives, although it is a less frequently celebrated achievement.