Patients May Return to Work Sooner After Laminoplasty: Occupational Outcomes of the Cervical Spondylotic Myelopathy Surgical Trial.

BACKGROUND AND OBJECTIVES: Return-to-work (RTW) is an important outcome for employed patients considering surgery for cervical spondylotic myelopathy (CSM). We conducted a post hoc analysis of patients as-treated in the Cervical Spondylotic Myelopathy Surgical Trial, a prospective, randomized trial comparing surgical approaches for CSM to evaluate factors associated with RTW. METHODS: In the trial, patients were randomized (2:3) to either anterior surgery (anterior cervical decompression/fusion [ACDF]) or posterior surgery (laminoplasty [LP], or posterior cervical decompression/fusion [PCDF], at surgeon's discretion). Work status was recorded at 1, 3, 6, and 12 months postoperatively. For patients working full-time or part-time on enrollment, time to RTW was compared across as-treated surgical groups using discrete-time survival analysis. Multivariate logistic regression was used to assess predictors of RTW. Clinical outcomes were compared using a linear mixed-effects model. RESULTS: A total of 68 (42%) of 163 patients were working preoperatively and were analyzed. In total, 27 patients underwent ACDF, 29 underwent PCDF, and 12 underwent LP. 45 (66%) of 68 patients returned to work by 12 months. Median time to RTW differed by surgical approach (LP = 1 month, ACDF = 3 months, PCDF = 6 months; P = .02). Patients with longer length-of-stay were less likely to be working at 1 month (odds ratio 0.51; 95% CI, 0.29-0.91; P = .022) and 3 months (odds ratio 0.39; 95% CI, 0.16-0.96; P = .04). At 3 months, PCDF was associated with lower Short-Form 36 physical component summary scores than ACDF (estimated mean difference [EMD]: 6.42; 95% CI, 1.4-11.4; P = .007) and LP (EMD: 7.98; 95% CI, 2.7-13.3; P = .003), and higher Neck Disability Index scores than ACDF (EMD: 12.48; 95% CI, 2.3-22.7; P = .01) and LP (EMD: 15.22; 95% CI, 2.3-28.1; P = .014), indicating worse perceived physical functioning and greater disability, respectively. CONCLUSION: Most employed patients returned to work within 1 year. LP patients resumed employment earliest, while PCDF patients returned to work latest, with greater disability at follow-up, suggesting that choice of surgical intervention may influence occupational outcomes.

The Accreditation Council for Graduate Medical Education 20-Year Trends in Diversity, Equity, and Inclusion in the United States: How Does Neurological Surgery Compare?

BACKGROUND: Within the current medical workforce, diversity is limited among surgical specialties. However, diversity allows physicians to provide culturally competent care. This paper discusses the trends in racial, ethnic, and gender representation within different surgical subspecialties with an emphasis on neurosurgery over a 20-year time frame. METHODS: A retrospective review of data collected by the Accreditation Council for Graduate Medical Education over the past twenty years, as reported in Journal of the American Medical Association, was conducted. Residents from 5 surgical specialties were evaluated based on gender, race, and ethnic identifications from 2002 to 2022. One-way analysis of variance was performed to compare the levels and retention rates of racial, ethnic, and gender diversity within these specialties. RESULTS: Analysis of resident demographics of the 5 surgical specialties reveals an overall trend of increasing diversity over the study period. Over the past 20 years, neurosurgery had an overall increase in Asian (+5.1%), Hispanic (+3.0%), and female (+11.4%) residents, with a decrease in White residents by 2.1% and Black residents by 1.1%. Among the surgical specialties analyzed, otolaryngology had the greatest overall increase in minority residents. Notably, there has been an overall increase in female residents across all 5 surgical specialties, with the highest in otolaryngology (+20.3%) which was significantly more than neurosurgery (P < 0.001). CONCLUSIONS: This chronological analysis spanning 20 years demonstrates that neurosurgery, like other specialties, has seen a growth in several racial and ethnic categories. Relative differences are notable in neurosurgery, including Black, Asian, Hispanic, and White ethnic categories, with growth in females, but at a significantly lesser pace than seen in otolaryngology and plastic surgery.

Augmenting Career Longevity: An Analysis of Ergonomics Training Among 134 Neurological Surgeons.

BACKGROUND: Work-related pain among neurosurgeons remains understudied, yet can have long-term consequences which affect operative efficiency and efficacy, career longevity, and life outside of work. OBJECTIVE: This study provides insight into the extent of pain experienced by neurosurgeons and the effect of ergonomics training on pain. METHODS: An online survey pertaining to ergonomics and pain was sent to all neurosurgeons on the Council of State Neurosurgical Societies (CSNS) email distribution list. Statistical comparisons of age groups against pain levels and ergonomics training against pain levels, as well as multivariate linear regression of demographics, training, and operating factors against pain levels were performed. RESULTS: One hundred and thirty-four neurosurgeons responded to the survey. The mean average severity of pain across respondents was 3.3/10 and the mean peak severity of pain was 5.1/10. Among the reported peak pain severity scores, neurosurgeons with 21-30 years of operating experience had significantly higher pain scores than those with 11-20 years of experience (mean 6.2 vs. 4.2; P < 0.05), while neurosurgeons with more than 30 years of experience had significantly less pain than those with 21-30 years of experience (mean 4.4 vs. 6.2, P = 0.005). Training in ergonomics did not significantly improve respondents' reported peak or mean pain severities (17.9% reported having ergonomics training). CONCLUSIONS: Ergonomics training did not appear to make a difference in neurosurgeons' pain severities. This may signify a need to optimize ergonomics pedagogy to achieve observable benefits.

Six-Year Follow-up of a Randomized Controlled Trial of i-FACTOR Peptide-Enhanced Bone Graft Versus Local Autograft in Single-Level Anterior Cervical Discectomy and Fusion.

BACKGROUND: Previous analyses of the US Food and Drug Administration (FDA) Investigational Device Exemption study demonstrated the superiority of i-FACTOR compared with local autograft bone in single-level anterior cervical discectomy and fusion (ACDF) at 12 and 24 months postoperatively in a composite end point of overall success. OBJECTIVE: To report the final, 6-year clinical and radiological outcomes of the FDA postapproval study. METHODS: Of the original 319 subjects enrolled in the Investigational Device Exemption study, 220 participated in the postapproval study (106 i-FACTOR and 114 control). RESULTS: The study met statistical noninferiority success for all 4 coprimary end points. Radiographic fusion was achieved in 99% (103/104) and 98.2% (109/111) in i-FACTOR and local autograft subjects, mean Neck Disability Index improvement from baseline was 28.6 (24.8, 32.3) in the i-FACTOR and 29.2 (25.6, 32.9) in the control group, respectively (noninferiority P < .0001). The neurological success rate at 6 years was 95.9% (70/73) in i-FACTOR subjects and 93.7% (70/75) in local autograft subjects (noninferiority P < .0001). Safety outcomes were similar between the 2 groups. Secondary surgery on the same or different cervical levels occurred in 20/106 (18.9%) i-FACTOR subjects and 23/114 (20.2%) local autograft subjects ( P = .866). Secondary outcomes (pain, SF-36 physical component score and mental component score) in i-FACTOR subjects were similar to those in local autograft subjects. CONCLUSION: i-FACTOR met all 4 FDA-mandated noninferiority success criteria and demonstrated safety and efficacy in single-level anterior cervical discectomy and fusion for cervical radiculopathy through 6 years postoperatively. Safety outcomes are acceptable, and the clinical and functional outcomes observed at 12 and 24 months remained at 72 months.

Laminectomy alone versus laminectomy with fusion for degenerative cervical myelopathy: a long-term study of a national cohort.

PURPOSE: To compare patient-reported 5-year clinical outcomes between laminectomy alone versus laminectomy with instrumented fusion in patients with degenerative cervical myelopathy in a population-based cohort. METHODS: All patients in the national Swedish Spine Register (Swespine) from January 2006 until March 2019, with degenerative cervical myelopathy, were assessed. Multiple imputation and propensity score matching based on clinicodemographic and radiographic parameters were used to compare patients treated with laminectomy alone with patients treated with laminectomy plus posterior-lateral instrumented fusion. The primary outcome measure was the European Myelopathy Score, a validated patient-reported outcome measure. The scale ranges from 5 to 18, with lower scores reflecting more severe myelopathy. RESULTS: Among 967 eligible patients, 717 (74%) patients were included. Laminectomy alone was performed on 412 patients (mean age 68 years; 149 women [36%]), whereas instrumented fusion was added for 305 patients (mean age 68 years; 119 women [39%]). After imputation, the propensity for smoking, worse myelopathy scores, spondylolisthesis, and kyphosis was slightly higher in the fusion group. After imputation and propensity score matching, there were on average 212 pairs patients with a 5-year follow-up in each group. There were no important differences in patient-reported clinical outcomes between the methods after 5 years. Due to longer hospitalization times and implant-related costs, the mean cost increase per instrumented patient was approximately $4700 US. CONCLUSIONS: Instrumented fusions generated higher costs and were not associated with superior long-term clinical outcomes. These findings are based on a national cohort and can thus be regarded as generalizable.

Lumbar Spine Surgery and What We Lost in the Era of the Coronavirus Pandemic: A Survey of the Lumbar Spine Research Society.

STUDY DESIGN: This was a survey of the surgeon members of the Lumbar Spine Research Society (LSRS). OBJECTIVE: The purpose of this study was to assess trends in surgical practice and patient management involving elective and emergency surgery in the early months of the coronavirus pandemic. SUMMARY OF BACKGROUND DATA: The novel coronavirus has radically disrupted medical care in the first half of 2020. Little data exists regarding the exact nature of its effect on spine care. METHODS: A 53-question survey was sent to the surgeon members of the LSRS. Respondents were contacted via email 3 times over a 2-week period in late April. Questions concentrated on surgical and clinical practice patterns before and after the pandemic. Other data included elective surgical schedules and volumes, as well as which emergency cases were being performed. Surgeons were asked about the status of coronavirus disease 2019 (COVID-19) virus testing. Circumstances for performing surgical intervention on patients with and without testing as well as patients testing positive were explored. RESULTS: A total of 43 completed surveys were returned of 174 sent to active surgeons in the LSRS (25%). Elective lumbar spine procedures decreased by 90% in the first 2 months of the pandemic, but emergency procedures did not change. Patients with "stable" lumbar disease had surgeries deferred indefinitely, even beyond 8 weeks if necessary. In-person outpatient visits became increasingly rare events, as telemedicine consultations accounted for 67% of all outpatient spine appointments. In total, 91% surgeons were under some type of confinement. Only 11% of surgeons tested for the coronavirus on all surgical patients. CONCLUSIONS: Elective lumbar surgery was significantly decreased in the first few months of the coronavirus pandemic, and much of outpatient spine surgery was practiced via telemedicine. Despite these constraints, spine surgeons performed emergency surgery when indicated, even when the COVID-19 status of patients was unknown. LEVEL OF EVIDENCE: Level IV.

An ACGME-based comparison of neurosurgical and orthopedic resident training in adult spine surgery via a case volume and hours-based analysis.

OBJECTIVE: In a 2014 analysis of orthopedic and neurological surgical case logs published by the Accreditation Council for Graduate Medical Education (ACGME), it was reported that graduating neurosurgery residents performed more than twice the number of spinal procedures in their training compared with graduating orthopedic residents. There has, however, been no follow-up assessment of this trend. Moreover, whether this gap in case volume equates to a similar gap in procedural hours has remained unstudied. Given the association between surgical volume and outcomes, evaluating the status of this disparity has value. Here, the authors assess trends in case volume and procedural hours in adult spine surgery for graduating orthopedic and neurological surgery residents from 2014 to 2019. METHODS: A retrospective analysis of ACGME case logs from 2014 to 2019 for graduating orthopedic and neurological surgery residents was conducted for adult spine surgeries. Case volume was converted to operative hours by using periprocedural times from the 2019 Medicare/Medicaid Physician Fee Schedule. Graduating residents' spinal cases and hours, averaged over the study period, were compared between the two specialties by using 2-tailed Welch's unequal variances t-tests (α = 0.05). Longitudinal trends in each metric were assessed by linear regression followed by cross-specialty comparisons via tests for equality of slopes. RESULTS: From 2014 to 2019, graduating neurosurgical residents logged 6.8 times as many spinal cases as their orthopedic counterparts, accruing 431.6 (95% CI 406.49-456.61) and 63.8 (95% CI 57.08-70.56) cases (p < 0.001), respectively. Accordingly, graduating neurosurgical residents logged 6.1 times as many spinal procedural hours as orthopedic surgery residents, accruing 1020.7 (95% CI 964.70-1076.64) and 166.6 (95% CI 147.76-185.35) hours (p < 0.001), respectively. Over these 5 years, both fields saw a linear increase in graduating residents' adult spinal case volumes and procedural hours, and these growth rates were higher for neurosurgery (+16.2 cases/year vs +4.4 cases/year, p < 0.001; +36.4 hours/year vs +12.4 hours/year, p < 0.001). CONCLUSIONS: Graduating neurosurgical residents accumulated substantially greater adult spinal case volumes and procedural hours than their orthopedic counterparts from 2014 to 2019. This disparity has been widened by a higher rate of growth in adult spinal cases among neurosurgery residents. Accordingly, targeted efforts to increase spinal exposure for orthopedic surgery residents-such as using cross-specialty collaboration-should be explored.

Effect of Ventral vs Dorsal Spinal Surgery on Patient-Reported Physical Functioning in Patients With Cervical Spondylotic Myelopathy: A Randomized Clinical Trial.

Importance: Cervical spondylotic myelopathy is the most common cause of spinal cord dysfunction worldwide. It remains unknown whether a ventral or dorsal surgical approach provides the best results. Objective: To determine whether a ventral surgical approach compared with a dorsal surgical approach for treatment of cervical spondylotic myelopathy improves patient-reported physical functioning at 1 year. Design, Setting, and Participants: Randomized clinical trial of patients aged 45 to 80 years with multilevel cervical spondylotic myelopathy enrolled at 15 large North American hospitals from April 1, 2014, to March 30, 2018; final follow-up was April 15, 2020. Interventions: Patients were randomized to undergo ventral surgery (n = 63) or dorsal surgery (n = 100). Ventral surgery involved anterior cervical disk removal and instrumented fusion. Dorsal surgery involved laminectomy with instrumented fusion or open-door laminoplasty. Type of dorsal surgery (fusion or laminoplasty) was at surgeon's discretion. Main Outcomes and Measures: The primary outcome was 1-year change in the Short Form 36 physical component summary (SF-36 PCS) score (range, 0 [worst] to 100 [best]; minimum clinically important difference = 5). Secondary outcomes included 1-year change in modified Japanese Orthopaedic Association scale score, complications, work status, sagittal vertical axis, health resource utilization, and 1- and 2-year changes in the Neck Disability Index and the EuroQol 5 Dimensions score. Results: Among 163 patients who were randomized (mean age, 62 years; 80 [49%] women), 155 (95%) completed the trial at 1 year (80% at 2 years). All patients had surgery, but 5 patients did not receive their allocated surgery (ventral: n = 1; dorsal: n = 4). One-year SF-36 PCS mean improvement was not significantly different between ventral surgery (5.9 points) and dorsal surgery (6.2 points) (estimated mean difference, 0.3; 95% CI, -2.6 to 3.1; P = .86). Of 7 prespecified secondary outcomes, 6 showed no significant difference. Rates of complications in the ventral and dorsal surgery groups, respectively, were 48% vs 24% (difference, 24%; 95% CI, 8.7%-38.5%; P = .002) and included dysphagia (41% vs 0%), new neurological deficit (2% vs 9%), reoperations (6% vs 4%), and readmissions within 30 days (0% vs 7%). Conclusions and Relevance: Among patients with cervical spondylotic myelopathy undergoing cervical spinal surgery, a ventral surgical approach did not significantly improve patient-reported physical functioning at 1 year compared with outcomes after a dorsal surgical approach. Trial Registration: ClinicalTrials.gov Identifier: NCT02076113.

Two-Year Clinical and Radiological Outcomes in Patients With Diabetes Undergoing Single-Level Anterior Cervical Discectomy and Fusion.

STUDY DESIGN: Secondary analysis of data from the multicenter, randomized, parallel-controlled Food and Drug Administration (FDA) investigational device exemption study. OBJECTIVE: Studies on outcomes following anterior cervical discectomy and fusion (ACDF) in individuals with diabetes are scarce. We compared 24-month radiological and clinical outcomes in individuals with and without diabetes undergoing single-level ACDF with either i-FACTOR or local autologous bone. METHODS: Between 2006 and 2013, 319 individuals with single-level degenerative disc disease (DDD) and no previous fusion at the index level underwent ACDF. The presence of diabetes determined the 2 cohorts. Data collected included radiological fusion evaluation, neurological outcomes, Neck Disability Index (NDI), Visual Analog Scale (VAS) scores, and the 36-Item Short Form Survey Version 2 (SF-36v2) Physical and Mental component summary scores. RESULTS: There were 35 individuals with diabetes (11.1%; average body mass index [BMI] = 32.99 kg/m2; SD = 5.72) and 284 without (average BMI = 28.32 kg/m2; SD = 5.67). The number of nondiabetic smokers was significantly higher than diabetic smokers: 73 (25.70%) and 3 (8.57%), respectively. Preoperative scores of NDI, VAS arm pain, and SF-36v2 were similar between the diabetic and nondiabetic participants at baseline; however, VAS neck pain differed significantly between the cohorts at baseline (P = .0089). Maximum improvement for NDI, VAS neck and arm pain, and SF-36v2 PCS and MCS scores was seen at 6 months in both cohorts and remained stable until 24 months. CONCLUSIONS: ACDF is effective for cervical radiculopathy in patients with diabetes. Diabetes is not a contraindication for patients requiring single-level surgery for cervical DDD.

Chronicling the philanthropic arm of neurological surgery: a review of the growth and development of the Neurosurgery Research & Education Foundation.

OBJECTIVE: The Neurosurgery Research & Education Foundation (NREF), previously known as the Research Foundation of the American Association of Neurological Surgeons (AANS), was established in 1980 to encourage and facilitate innovation through financial support to young neurosurgeons in the process of honing their competencies in neurosciences and neurological surgery. This article provides a historical overview of NREF, its mission, and charitable contributions and the ever-expanding avenues for neurosurgeons, neurosurgical residents and fellows, and medical students to supplement clinical training and to further neurosurgical research advances. METHODS: Data were collected from the historical archives of the AANS and NREF website. Available data included tabulated revenue, geographic and institutional records of funding, changes in funding for fellowships and awards, advertising methods, and sources of funding. RESULTS: Since 1984, NREF has invested more than $23 million into the future of neurosurgery. To date, NREF has provided more than 500 fellowship opportunities which have funded neurosurgeons' education and research efforts at all stages of training and practice. CONCLUSIONS: NREF is designed to serve as the vehicle through which the neurosurgical community fosters the continued excellence in the care of patients with neurosurgical diseases.

Contributions to the Neurosurgery Political Action Committee (NeurosurgeryPAC): A Historical Perspective.

BACKGROUND: The political action committee (PAC) of the American Association of Neurological Surgeons, known as NeurosurgeryPAC, was formed in August 2005 to strengthen neurosurgical advocacy efforts. Since its establishment, NeurosurgeryPAC has made nonpartisan, direct campaign contributions to hundreds of candidates for the U.S. Senate and U.S. House of Representatives. METHODS: Historical contribution data for 2005-2018 was obtained from NeurosurgeryPAC. Data analyzed by year, and a 2-year election cycle included total amount raised, number of contributors, average donation, and percent participation. NeurosurgeryPAC contribution amounts for election cycles were also compared with those of other physician PACs. RESULTS: NeurosurgeryPAC has raised $2,953,870 since its inception in 2005, for an average of $210,991 per year. For this fundraising, the average annual donation amount is $796 per donor. The number of unique contributors per cycle has varied from 316-504, with an average of 389 individuals per annum and a participation rate of 7.8%. To date, the total amount raised in election years ($1,605,940) is 16.1% higher than that raised in nonelection years ($1,347,930). Among 28 physician PACs, NeurosurgeryPAC has ranked as high as 13 and as low as 17 in total hard money contributions. The orthopedic, neurology and general surgery PACs have consistently ranked higher than NeurosurgeryPAC, whereas the otolaryngology, spine, and plastic surgery PACs have ranked lower. CONCLUSIONS: Since its creation, NeurosurgeryPAC has collected a steady stream of donations to support political candidates. These donations have helped lawmakers who are supportive of policy issues important to neurosurgery, particularly physician reimbursement, medical liability reform, and graduate medical education. However, there remains a significant opportunity to increase the neurosurgeon participation rate in this vital organization. It is truly through advocacy that we will be able to positively affect the future of neurologic surgery in the United States.

Pathological pain processing in mouse models of multiple sclerosis and spinal cord injury: contribution of plasma membrane calcium ATPase 2 (PMCA2).

BACKGROUND: Neuropathic pain is often observed in individuals with multiple sclerosis (MS) and spinal cord injury (SCI) and is not adequately alleviated by current pharmacotherapies. A better understanding of underlying mechanisms could facilitate the discovery of novel targets for therapeutic interventions. We previously reported that decreased plasma membrane calcium ATPase 2 (PMCA2) expression in the dorsal horn (DH) of healthy PMCA2+/- mice is paralleled by increased sensitivity to evoked nociceptive pain. These studies suggested that PMCA2, a calcium extrusion pump expressed in spinal cord neurons, plays a role in pain mechanisms. However, the contribution of PMCA2 to neuropathic pain processing remains undefined. The present studies investigated the role of PMCA2 in neuropathic pain processing in the DH of wild-type mice affected by experimental autoimmune encephalomyelitis (EAE), an animal model of MS, and following SCI. METHODS: EAE was induced in female and male C57Bl/6N mice via inoculation with myelin oligodendrocyte glycoprotein fragment 35-55 (MOG35-55) emulsified in Complete Freund's Adjuvant (CFA). CFA-inoculated mice were used as controls. A severe SC contusion injury was induced at thoracic (T8) level in female C57Bl/6N mice. Pain was evaluated by the Hargreaves and von Frey filament tests. PMCA2 levels in the lumbar DH were analyzed by Western blotting. The effectors that decrease PMCA2 expression were identified in SC neuronal cultures. RESULTS: Increased pain in EAE and SCI was paralleled by a significant decrease in PMCA2 levels in the DH. In contrast, PMCA2 levels remained unaltered in the DH of mice with EAE that manifested motor deficits but not increased pain. Interleukin-1ß (IL-1ß), tumor necrosis factor α (TNFα), and IL-6 expression were robustly increased in the DH of mice with EAE manifesting pain, whereas these cytokines showed a modest increase or no change in mice with EAE in the absence of pain. Only IL-1ß decreased PMCA2 levels in pure SC neuronal cultures through direct actions. CONCLUSIONS: PMCA2 is a contributor to neuropathic pain mechanisms in the DH. A decrease in PMCA2 in DH neurons is paralleled by increased pain sensitivity, most likely through perturbations in calcium signaling. Interleukin-1ß is one of the effectors that downregulates PMCA2 by acting directly on neurons.

Surgical Treatment With Thoracic Pedicle Screw Fixation of Vertebral Osteomyelitis With Long-Term Follow-up.

BACKGROUND: While recent data has demonstrated the utility of lumbar pedicle screws for the treatment of vertebral osteomyelitis, the data are limited for thoracic pedicle screws. OBJECTIVE: To investigate the effectiveness of thoracic pedicle screws for the surgical treatment of vertebral osteomyelitis. METHODS: A retrospective review of all operations performed by 2 spinal neurosurgeons from 1999 to 2012 yielded 30 cases of vertebral osteomyelitis that were treated with thoracic pedicle screws. Sixteen (53%) of which underwent combined anterior and posterior fusion and 14 patients (47%) underwent standalone posterior fusion. Postoperative records were analyzed for pertinent clinical, laboratory, and radiographic data. RESULTS: Of the 30 patients, 21 were males (70%), 8 were females (27%), and 1 was transsexual (3%). The mean age was 47 yr (range 18-69). The most common organism cultured was Staphylococcus aureus in 12 cases (50%). The mean patient stay in the hospital was 12.4 d after surgery (range 5-38 d). The mean antibiotic duration after discharge was 8 wk (range 1-24 wk). Of the 25 patients with long-term follow-up (mean, 49 mo), 92% had improved back pain (6/25 marked improvement, 17/25 complete resolution), 83% had improved muscle weakness (8/18 marked improvement, 7/18 complete resolution), and 100% had improved urinary incontinence (3/8 marked improvement, 5/8 complete resolution). Two patients (7%) required additional surgical revision due to instrumentation failure or wound infection. CONCLUSION: This study demonstrates the efficacy of utilizing thoracic pedicle screws as a primary intervention to treat vertebral osteomyelitis.

A link between plasma membrane calcium ATPase 2 (PMCA2), estrogen and estrogen receptor α signaling in mechanical pain.

Earlier studies on genetically modified mice indicated that plasma membrane calcium ATPase 2 (PMCA2), a calcium extrusion pump, plays a novel and sex-dependent role in mechanical pain responses: female, but not male, PMCA2+/- mice manifest increased mechanical pain compared to female PMCA2+/+ mice. The goal of the present studies was to determine the contribution of ovarian steroids to the genotype- and sex-dependent manifestation of mechanical pain in PMCA2+/+ versus PMCA2+/- mice. Ovariectomy increased mechanical pain sensitivity and 17ß-estradiol (E2) replacement restored it to basal levels in PMCA2+/+ mice, but not in PMCA2+/- littermates. Intrathecal administration of an estrogen receptor alpha (ERα) agonist induced ERα signaling in the dorsal horn (DH) of female PMCA2+/+ mice, but was ineffective in PMCA2+/- mice. In male PMCA2+/+ and PMCA2+/- mice, E2 treatment following orchidectomy did not recapitulate the genotype-dependent differential pain responses observed in females and the agonist did not elicit ERα signaling. These findings establish a novel, female-specific link between PMCA2, ERα and mechanical pain. It is postulated that PMCA2 is essential for adequate ERα signaling in the female DH and that impaired ERα signaling in the female PMCA2+/- mice hinders the analgesic effects of E2 leading to increased sensitivity to mechanical stimuli.

Novel Association Between Intrathecal Drug Administration and Arachnoiditis Ossificans.

BACKGROUND: We present a case of delayed progression of adhesive arachnoiditis to arachnoiditis ossificans (AO) in a patient being treated with a high-dose polypharmaceutical intrathecal regimen. CASE DESCRIPTION: The patient is a 39-year-old Caucasian male who was implanted with an intrathecal pump in 2006 to control severe low back pain and administered intrathecal pain medication for a period of 10 years. In 2016, he developed new-onset radicular pain and worsened sensation in his lower extremities. Computed tomography scan of the lumbar spine at that time demonstrated profound calcification of the arachnoid consistent with a diagnosis of AO. It was presumed that prolonged high-dose intrathecal medication precipitated this condition, and his intrathecal medications were titrated down with removal of the pump. CONCLUSIONS: It is unlikely that his condition occurred as a result of prior surgery, with the more likely cause being hyperplasia of the spinal arachnoid, leading to scarring and calcification, due to the high-dose intrathecal regimen. This case highlights the delayed progression from stable arachnoiditis to AO concurring with a regimen of high-dose intrathecal medications. Clinicians should closely monitor patients undergoing intrathecal drug administration, particularly at elevated doses, for indications of damage to the spinal arachnoid mater.

Previously unreported complications associated with integrated cage screws following anterior lumbar interbody fusion: report of 2 cases.

Anterior lumbar interbody fusion (ALIF) is a widely performed surgical treatment for various lumbar spine pathologies. The authors present the first reports of virtually identical cases of complications with integrated screws in stand-alone interbody cages. Two patients presented with the onset of S-1 radiculopathy due to screw misplacements following an ALIF procedure. In both cases, an integrated screw from the cage penetrated the dorsal aspect of the S-1 cortical margin of the vertebra, extended into the neural foramen, and injured the traversing left S-1 nerve roots. Advanced neuroimaging findings indicated nerve root impingement by the protruding screw tip. After substantial delays, radiculopathic symptoms were treated with removal of the offending instrumentation, aggressive posterior decompression of the bony and ligamentous structures, and posterolateral fusion surgery with pedicle screw fixation. Postoperative radiographic findings demonstrated decompression of the symptomatic nerve roots via removal of the extruded screw tips from the neural foramina.

i-Factor™ Bone Graft vs Autograft in Anterior Cervical Discectomy and Fusion: 2-Year Follow-up of the Randomized Single-Blinded Food and Drug Administration Investigational Device Exemption Study.

BACKGROUND: i-Factor™ Bone Graft (Cerapedics Inc, Westminster, Colorado) is a composite bone substitute material consisting of P-15 synthetic collagen fragment adsorbed onto anorganic bone mineral suspended in an inert biocompatible hydrogel carrier. A pivotal, noninferiority, US FDA Investigational Device Exemption study demonstrated the benefits of i-Factor™ compared to local autograft bone in single-level anterior cervical discectomy and fusion at 1-yr postoperative. OBJECTIVE: To report 2-yr follow-up. METHODS: Subjects randomly received either autograft (n = 154) or i-Factor™ (n = 165) in a cortical ring allograft and followed using radiological, clinical, and patient-reported outcomes. RESULTS: At 2 yr, the fusion rate was 97.30% and 94.44% in i-Factor™ and autograft subjects, respectively (P = .2513), and neurological success rate was 94.87% (i-Factor™) and 93.79% (autograft; P = .7869). Neck Disability Index improved 28.30 (i-Factor™) and 26.95 (autograft; P = .1448); Visual Analog Scale arm pain improved 5.43 (i-Factor™) and 4.97 (autograft) (p = .2763); Visual Analog Scale neck pain improved 4.78 (i-Factor™) and 4.41 (autograft; P = .1652), Short Form-36 (SF-36v2) Physical Component Score improved 10.23 (i-Factor™) and 10.18 (autograft; P = .4507), and SF36v2 Mental Component Score improved 7.88 (i-FactorTM) and 7.53 (autograft; P = .9872). The composite endpoint of overall success (fusion, Neck Disability Index improvement >15, neurological success, and absence of re-operations) was greater in i-Factor™ subjects compared to autograft subjects (69.83% and 56.35%, respectively, P = .0302). Twelve (7.45%) i-Factor™ subjects and 16 (10.53%) autograft subjects underwent re-operation (P = .3411). There were no allergic reactions associated with i-Factor™. CONCLUSION: Use of i-Factor™ in anterior cervical discectomy and fusion is effective and safe, and results in similar outcomes compared to local autograft bone at 2 yr following surgery.

Elastic modulus in the selection of interbody implants.

BACKGROUND: The modulus of elasticity of an assortment of materials used in spinal surgery, as well as cortical and cancellous bones, is determined by direct measurements and plotting of the appropriate curves. When utilized in spine surgery, the stiffness of a surgical implant can affect its material characteristics. The modulus of elasticity, or Young's modulus, measures the stiffness of a material by calculating the slope of the material's stress-strain curve. While many papers and presentations refer to the modulus of elasticity as a reason for the choice of a particular spinal implant, no peer-reviewed surgical journal article has previously been published where the Young's modulus values of interbody implants have been measured. METHODS: Materials were tested under pure compression at the rate of 2 mm/min. A maximum of 45 kilonewtons (kN) compressive force was applied. Stress-strain characteristics under compressive force were plotted and this plot was used to calculate the elastic modulus. RESULTS: The elastic modulus calculated for metals was more than 50 Gigapascals (GPa) and had significantly higher modulus values compared to poly-ether-ether-ketone (PEEK) materials and allograft bone. CONCLUSIONS: The data generated in this paper may facilitate surgeons to make informed decisions on their choices of interbody implants with specific attention to the stiffness of the implant chosen.