Cooled radiofrequency ablation of the sacroiliac joint a retrospective case series.

BACKGROUND: Sacroiliac (SI) joint dysfunction is a common source of back pain. Recent evidence from different parts of the world suggest that cooled radiofrequency ablation of sacral nerves supplying the SI joints has superior pain alleviating properties than currently available treatment options for SI joint dysfunction. PATIENTS AND METHODS: After obtaining institutional review board approval, the medical records of 81 patients who underwent cooled radiofrequency ablation in a single institution and by a single surgeon were analyzed retrospectively. The recurrence of pain, progression to fusion and functional outcomes were noted. The patients were operated on between June 2020 and December 2021, they include 59 females and 22 males, the average age was 55.4 ± 17.3. Follow up was at least 6 months postoperative. RESULTS: 22 of the patients had previously underwent lumbar fusions. Follow up period ranged from 6 to 18 months. After radiofrequency ablation, 7 patients progressed to fusions, and 6 patients had to have the procedure done again to relieve their pain. Student t-test was used to compare between preoperative and postoperative values of NPRS (numerical pain rating score) and ODI (Oswestry disability index). It showed significance with P-value < 0.001 in both. CONCLUSIONS: Sacroiliac joint radiofrequency ablation is a good option in the treatment of SI joint pain showing good results in the short term follow up period. It is a simple procedure that can be done in less than 30 min and is capable of providing significant pain relief for patients with sacroiliac joint dysfunction.

Reference values of four measures of craniocervical stability using upright dynamic magnetic resonance imaging.

PURPOSE: To establish reference ranges for four most commonly used diagnostic measures of craniocervical instability (CCI) in three cervical sagittal positions. This necessitated development of a reliable measurement protocol using upright, dynamic MRI (udMRI), to determine differences in the extent of motion between positions, and whether age and sex correlate with these measures. MATERIALS AND METHODS: Deidentified udMRIs of 50 adults, referred for reasons other than CCI, were captured at three positions (maximal flexion, maximal extension and neutral). Images were analyzed, providing measures of basion-axial interval, basion-axial angle, basion-dens interval (BDI) and the Grabb-Oakes line (GOL) for all three positions (12 measures per participant). All measures were independently recorded by a radiologist and neurosurgeon to determine their reliability. Descriptive statistics, correlations, paired and independent t-tests were used. Mean (± 2 SD) identified the reference range for all four measures at each craniocervical position. RESULTS: The revised measurement protocol produced inter-rater reliability indices of 0.69-0.97 (moderate-excellent). Fifty adults' (50% male; mean age 41.2 years (± 9.7)) reference ranges for all twelve measures were reported. Except for the BDI and GOL when moving between neutral and full flexion, significant extents of movement were identified between the three craniocervical positions for all four measures (p ≤ 0.005). Only a minor effect of age was found. CONCLUSIONS: This is the first study to provide a rigorous standardized protocol for four diagnostic measures of CCI. Reference ranges are established at mid and ends of sagittal cervical range corresponding to where exacerbations of signs and symptoms are commonly reported.

Treating multi-level cervical disc disease with hybrid surgery compared to anterior cervical discectomy and fusion: a systematic review and meta-analysis.

PURPOSE: The traditional surgical approach to treat multi-level cervical disc disease (mCDD) has been anterior cervical discectomy and fusion (ACDF). There has been recent development of other surgical approaches to further improve clinical outcomes. Collectively, when elements of these different approaches are combined in surgery, it is known as hybrid surgery (HS) which remains a novel treatment option. A systematic review and meta-analysis was conducted to compare the outcomes of HS versus ACDF for the treatment of mCDD. METHODS: Relevant articles were identified from six electronic databases from their inception to January 2016. RESULTS: From 8 relevant studies identified, 169 patients undergoing HS were compared with 193 ACDF procedures. Operative time was greater after HS by 42 min (p < 0.00001), with less intraoperative blood loss by 26 mL (p < 0.00001) and shorter return to work by 32 days (p < 0.00001). In terms of clinical outcomes, HS was associated with greater C2-C7 range of motion (ROM) preservation (p < 0.00001) and less functional impairment (p = 0.008) after surgery compared to ACDF. There was no significant difference between HS and ACDF with respect to postoperative pain (p = 0.12). The postoperative course following HS was not significantly different to ACDF in terms of length of stay (p = 0.24) and postoperative complication rates (p = 0.18). CONCLUSIONS: HS is a novel surgical approach to treat mCDD, associated with a greater operative time, less intraoperative blood loss and comparable if not superior clinical outcomes compared to ACDF. While it remains a viable consideration, there is a lack of robust clinical evidence in the literature. Future large prospective registries and randomised trials are warranted to validate the findings of this study.

Minimally invasive versus open transforaminal lumbar interbody fusion for treatment of degenerative lumbar disease: systematic review and meta-analysis.

PURPOSE: While open TLIF (O-TLIF) remains the mainstay approach, minimally invasive TLIF (MI-TLIF) may offer potential advantages of reduced trauma to paraspinal muscles, minimized perioperative blood loss, quicker recovery and reduced risk of infection at surgical sites. This meta-analysis was conducted to provide an updated assessment of the relative benefits and risks of MI-TLIF versus O-TLIF. METHODS: Electronic searches were performed using six databases from their inception to December 2014. Relevant studies comparing MI-TLIF and O-TLIF were included. Data were extracted and analysed according to predefined clinical end points. RESULTS: There was no significant difference in operation time noted between MI-TLIF and O-TLIF cohorts. The median intraoperative blood loss for MI-TLIF was significantly lower than O-TLIF (median: 177 vs 461 mL; (weighted mean difference) WMD, -256.23; 95% CI -351.35, -161.1; P < 0.00001). Infection rates were significantly lower in the minimally invasive cohort (1.2 vs 4.6%; relative risk (RR), 0.27; 95%, 0.14, 0.53; I2) = 0%; P = 0.0001). VAS back pain scores were significantly lower in the MI-TLIF group compared to O-TLIF (WMD, -0.41; 95% CI -0.76, -0.06; I2 = 96%; P < 0.00001). Postoperative ODI scores were also significantly lower in the minimally invasive cohort (WMD, -2.21; 95% CI -4.26, -0.15; I2 = 93%; P = 0.04). CONCLUSIONS: In summary, the present systematic review and meta-analysis demonstrated that MI-TLIF appears to be a safe and efficacious approach compared to O-TLIF. MI-TLIF is associated with lower blood loss and infection rates in patients, albeit at the risk of higher radiation exposure for the surgical team. The long-term relative merits require further validation in prospective, randomized studies.

Does preoperative imaging for scalp non-melanocytic skin cancer accurately predict invasion of the cranial vault? A systematic review and meta-analysis.

PURPOSE: This study aimed to determine the diagnostic accuracy of CT and MRI in the preoperative detection of bone involvement for non-melanoma skin cancers (NMSCs) located on the scalp. This study further aimed to evaluate the predictive value of these imaging modalities in determining the need for craniectomy and to identify gaps in the existing literature. METHODS: Electronic searches of the MEDLINE, Embase, Cochrane and Google Scholar databases were performed for English language studies of any type. Studies reporting detection or exclusion of histopathologically confirmed bone involvement through preoperative imaging were identified according to PRISMA guidelines. Studies reporting dural involvement, non-scalp tumours, and lacking tumour type(s) or outcome data were excluded. Outcomes were preoperative imaging result and histopathologically confirmed bone invasion. Meta-analysis was performed and sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) were calculated (excluding case report and MRI data due to insufficient quality and quantity respectively). RESULTS: Four studies with a total of 69 patients were included in the final review, of which two studies totalling 66 patients were included in the meta-analysis. Preoperative CT had a sensitivity of 38%, specificity of 98%, PPV of 90% and NPV of 73%. CONCLUSIONS: The available data suggests that a preoperative CT finding of calvarial involvement by a scalp NMSC is likely to be real, but the absence of such a finding is unreliable. Current evidence suggests that preoperative imaging cannot exclude the necessity for craniectomy and future research is needed, particularly on the role of MRI.

The Incidence of Pars Interarticularis Defects in Athletes.

STUDY DESIGN: Literature review. OBJECTIVE: To conduct a literature review of studies reporting the incidence of pars interarticularis defects in athletes of specific sports, in order to allow more targeted prevention and treatment strategies to be implemented for the groups at highest risk. METHODS: Electronic searches were performed using PubMed, Ovid Medline, EMBASE, Google Scholar, Cochrane Database of Systematic Reviews, and Cochrane Database of Controlled Trials from their dates of inception to September 2017, with the following keywords: "spondylolysis," "sports," "low back pain," and "pars defects." RESULTS: A total of 509 total articles were retrieved, of which 114 were used in the final review. The incidence of pars interarticularis defects was found to be highest in diving (35.38%), cricket (31.97%), baseball/softball (26.91%), rugby (22.22%), weightlifting (19.49%), sailing (17.18%), table tennis (15.63%), and wrestling (14.74%). Only 5 studies reported the management instituted for their participants, and these were all case reports. Of 74 players with spondylolysis in these studies, 70 (94.59%) underwent conservative treatment and 4 (5.41%) underwent surgical treatment. 61 (82.43%) returned to their previous level of play, 6 (8.11%) retired, and the disposition of the final 7 was not reported. CONCLUSION: The current medical literature provides good evidence that the incidence of pars interarticularis defects is higher in the athletic population, with the highest incidence in diving. There remains no gold standard protocol for the management of pars interarticularis defects. Further research is required to compare conservative therapy to surgical therapy and to compare the various surgical techniques to each other.

Degenerate-disc infection study with contaminant control (DISC): a multicenter prospective case-control trial.

BACKGROUND: A bacterial cause of disc degeneration has evoked several controversies and, if true, would lead to a major shift in treatment paradigm. Earlier studies analyzing the relationship of bacterial disc infection within a degenerative cohort featured prolonged cultures susceptible to contamination. The degenerate-disc infection study with contaminant control (DISC) trial aims to investigate this theory further by examining infection rates using a non-degenerative control cohort in comparison to a degenerative internal control cohort and a sham cohort (sampling only sterile paraspinal tissue). To our knowledge, the current study is the largest evaluating the growth of organisms (or possible contamination rate) in paraspinal tissue if prolonged cultures are performed. Protocols on methodology have been previously published. PURPOSE: (1) To investigate the infection rates across cohorts (degenerative vs. nondegenerative control; paraspinal and/or disc controls vs. combined sampling cohorts) using stringent standardized aseptic surgical technique and laboratory processing. (2) To compare our findings to that of the literature and make a statement in support and/or against a possible contamination theory to positive cultures. STUDY DESIGN: Multicenter, multisurgeon case-control trial. PATIENT SAMPLE: In all, 812 surgical samples were retrieved across a 3.5-year period (2013-2016) including 25 trauma controls (nondegenerative), 550 "disc and paraspinal" samples (degenerative cases with internal control), 190 disc-only samples (degenerative cases without internal control), and 46 paraspinal only controls (sham group). OUTCOME MEASURES: Growth and/or Contamination rate (%) per cohort. Chi-square of growth in disc versus paraspinal samples as a means of examining the distribution of false positive and contaminant growth. The impact of previous injections and/or surgery on positive disc or paraspinal growth. Correlation of Modic changes with positive growth rates analyzed with the Kruskal-Wallis Test. The distribution of species in positive samples were also analyzed. METHODS: The DISC trial is registered under Australian and New Zealand clinical trials registry-ACTRN12616000541404. Institutional ethics review was obtained (HREC northern sector 13/218) at the primary center and further centers (n=6) were recruited. Patients undergoing spinal surgery with discectomy were eligible for trial entry with tissue specimens obtained using strict aseptic technique for microbiological examination. All specimens were handled with sterile instruments only and by a fresh instrument to a sterile pot that was closed immediately. Separate pots were used for the disc and paraspinal tissue respectively with similar stringent processing during microbiological assessment. A cohort of the degenerative cases at one single institution also underwent an additional histopathological examination. RESULTS: There was an expected significant difference in gender and age associated with the non-degenerative control group (due to trauma patients) compared with other cohorts. There was a higher percentage of positive-growth in the control group in comparison to the disc and paraspinal and disc only groups across positive disc growth (48% vs. 27% vs. 17%, p<.001). A similar infection rate was observed in the paraspinal samples across the equivalent controls (44% vs. 36% vs. 37%, p=.739). There was a significant difference in the proportions of positive growth with a large proportion of false positives (growth in both disc and paraspinal samples; p<.001). There was no difference in true positive growth between the case and control groups (16.0 vs. 7.7%, p=.112). These trends were preserved across all cohorts and when stratifying by spinal segment (cervical or lumbar). There was no correlation between Modic changes and positive disc culture growth (p=.398, n=144 samples). Cutibacterium (formerly Propionibacterium) acnes was the most dominant pathogen isolated, representing between 50% and 70% of positive disc and paraspinal specimens, followed by staphylococcal species. CONCLUSIONS: Our study failed to find a difference in true infection rates between the nondegenerative and degenerative disc populations. These findings are suggestive of a contamination theory and against a common infective etiology in the setting of discogenic back and neck pain. We believe the rationale for antibiotic therapy in the management of discogenic back pain warrants further evidence to establish efficacy.

Dabigatran reversal by idarucizumab in the setting of intracranial hemorrhage: A systematic review of the literature.

Idarucizumab is the first Food and Drugs Administration (FDA) approved reversal agent for anticoagulant dabigatran, a direct thrombin inhibitor. Emerging evidence suggests idarucizumab can improve clinical outcome following dabigatran-associated hemorrhage, however, its specific use in intracranial hemorrhage has been poorly described. The aim of this study was to systematically review the available literature of idarucizumab in the setting of dabigatran-associated ICH to evaluate its efficacy in the stabilizing/resolving of the primary hemorrhage. A systematic search of 7 electronic databases from their earliest records to August 2018 was conducted following the Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) guidelines. There were 864 articles identified for screening against selection criteria. The search identified 9 articles to be included in our analysis, describing hemorrhage outcomes in 23 dabigatran-associated cases of ICH managed by idarucizumab. Mean overall age was 76.2 years, with 43% females, and bleeding was subdural, subarachnoid and intracerebral in 43%, 13% and 43% cases respectively. Surgical intervention was pursued in 48% of cases. During the course of the hospitalization, the hemorrhages stabilized/resolved in 87% of patients, and worsened in 13%. In-hospital complications occurred in 4% of cases, and mortality occurred in 4% of cases as well. The available literature suggests that idarucizumab can be applied in the setting of ICH, for its therapeutic effect in patients presenting with dabigatran-associated ICH appears acceptable with no compromise to clinical safety. However, currently there is a paucity of data about various aspects that are involved in other aspects of ICH treatment, including recovery, that limits the significance of the current literature. As more evidence is published relating specifically to long-term ICH outcomes that have been treated by idarucizumab, we will be better placed to establish the optimal role of idarucizumab in the setting of dabigatran-associated ICH.

Outcomes of direct lateral interbody fusion (DLIF) in an Australian cohort.

BACKGROUND: Direct lateral interbody fusion (DLIF) mitigates many of the vascular complications and bony resections associated with other interbody fusion techniques. However, there are concerns regarding postoperative neural complications and that indirect decompression of the foramen has not been consistently demonstrated. This study prospectively assessed the clinical and radiological outcomes and the complication rates of the DLIF approach. METHODS: A prospective review was conducted of the first 50 consecutive DLIF cases of a single neurosurgeon between 2010 and 2014. Clinical outcomes were assessed using Visual Analogue Scale (VAS), Oswestry Disability Index (ODI) and Roland Morris Disability Questionnaire (RMDQ) surveys. Radiological outcomes, including spondylolisthesis, disc height, local disc angle, lumbar lordosis and foraminal height and width, were measured using Surgimap Spine software at the preoperative, 6 weeks, 6 months, and 12 months postoperative follow-up. Complication rates were also reported. RESULTS: A total of 50 patients (84 levels) were treated with DLIF. The mean patient age was 68.2±9.8 years and 62.0% were female. At latest follow-up, mean VAS pain score improved from 7.7±1.5 to 1.9±0.9 (P<0.0001), mean ODI improved from 42.1±14.5 to 16.9±6.7 (P<0.0001) and mean RMDQ score improved from 12.1±5.2 to 6.2±4.7 (P<0.0001). Mean spondylolisthesis reduced from 7.5%±6.5% to 1.3%±1.1% at 6 weeks (P<0.0001), 0.95%±0.74% at 6 months (P<0.0001) and recurred to 1.9%±1.7% at 12 months postoperatively (P=0.0006). Mean anterior disc height improved from 7.3±3.2 to 11.6±2.5 mm at 6 weeks (P<0.0001), 12.2±3.3 mm at 6 months (P<0.0001) and 9.8±2.1 mm at 12 months (P=0.0032) postoperatively. Mean posterior disc height improved from 4.4±2.0 to 6.8±2.1 mm at 6 weeks (P<0.0001), 6.6±2.5 mm at 6 months (P=0.0003), and 5.9±1.4 mm at 12 months (P=0.0039) postoperatively. Mean local disc angle improved from 7.0°±3.7° to 9.2°±3.3° at 6 weeks (P=0.0072), 10.4°±3.9° at 6 months (P=0.0013) and 8.2°±2.9° at 12 months (P=0.2487) postoperatively. No significant postoperative changes in lumbar lordosis were observed. Mean foraminal height improved from 18.3±3.5 to 21.5±3.9 mm at 6 weeks (P=0.0004), 20.6±3.4 mm at 6 months (P=0.0266), and 18.7±1.9 mm at 12 months (P=0.8021) postoperatively. Mean foraminal width improved from 7.9±2.0 to 10.2±2.8 mm at 6 weeks (P=0.0001), 9.4±2.6 mm at 6 months (P=0.0219) and 8.3±1.6 mm at 12 months (P=0.5734) postoperatively. Fusion rate at 6 and 12 months was 62.2% and 89.2%, respectively. A total of 6 patients (12%) had postoperative complications. Three patients (6%) had pain-related psoas muscle weakness and 3 patients (6%) had sensory neural complications that had resolved entirely by 8 and 16 weeks postoperatively, respectively. CONCLUSIONS: The study provides encouraging short and medium-term clinical and radiological results for DLIF. In this patient series, there was a low complication rate with no permanent neural injury reported.

Degenerate-disc infection study with contaminant control (DISC): Application of a proposed histological scoring system.

Recent evidence into an infectious etiology of discogenic back pain/leg pain are ongoing with contradictory data in literature. We sought to validate the clinical relevance of histopathological evidence of inflammation through a previously proposed histological grading system. In this prospective cohort study, 124 consecutive patients undergoing an elective spinal decompression and/or fusion procedure involving discectomy were selected with intraoperative tissue sampling of intervertebral disc and paraspinal tissue at a single institution. The histological domains were correlated with positive disc cultures to assist in identifying relevant positive infections. Inter-observer analysis of the scoring system was also performed. There were 124 samples (36 cervical and 88 lumbar) obtained. 29 (23.4%) disc specimens and 37 (29.8%) of ligament samples demonstrated growth of C. acnes. In total, 38/124 (30.6%) of disc specimens were positive for growth of any species. There was poor association between positive disc culture and the presence of neutrophilia (p = 0.123) or chronic inflammatory changes (p = 0.092) on histopathological assessment. There was no statistical significance noted across all histological domains examined within the finalised scoring system and positive culture across disc specimens. There was moderate agreement in between observers (kappa range: 0.41-0.60) in the assessment of inflammatory changes using the proposed scoring system. The current study suggests poor correlation between histopathological evidence of chronic or acute inflammation and positive disc cultures questioning the idea that disc infection is the root cause of acute or chronic back pain/leg pain.

Integral Fixation Titanium/Polyetheretherketone Cages for Cervical Arthrodesis: Evolution of Cage Design and Early Radiological Outcomes and Fusion Rates.

OBJECTIVE: To evaluate the initial outcomes of a composite cage with integral fixation using the Redmond titanium (Ti)/polyetheretherketone (PEEK) anterior cervical discectomy and fusion (ACDF) device. METHODS: Data from 50 consecutive patients were prospectively collected from a single senior surgeon cohort. All cages were between 5 and 8 mm in height, and were packed with supercritical CO2 sterilized allograft. Patients were followed up for a minimum of 6 months, and implant complications were assessed. RESULTS: From the original cohort, three were unavailable for follow-up. Forty-seven patients with a total of 58 operative levels were observed for a mean of 7.9 months. A fusion rate of 96% was achieved. Good to excellent outcomes were seen in 92% of patients. There were no cases of implant Ti/PEEK delamination or implant failure, with excellent early fusion rates using supercritical CO2 allograft. CONCLUSIONS: The present study demonstrates the development of a composite ACDF cage design that is a safe and effective treatment option with the potential for early osseointegration and interbody fusion. Supercritical CO2 sterilized allograft was an effective graft material supporting fusion.

Clinical and functional outcomes of anterior cervical discectomy without fusion.

Anterior cervical discectomy without fusion is an effective treatment for myeloradiculopathy arising from a medial disc prolapse. However, the long-term clinical results are not well known. Between 2000 and 2006, 38 patients with persistent radiculopathy and medial disc prolapse or myelopathy due to acute disc prolapse underwent subtotal anterior cervical discectomy without fusion. Patients were evaluated with respect to pain, myelopathy and functional outcome. Thirty-four patients were followed up for an average of 48.6 months. Following surgery, neck pain improved by 69% in 88% of patients, arm pain improved by 76% in 91% of patients and 76% of the patients were able to resume working in their previous occupation. We conclude anterior cervical decompression without fusion can be associated with good clinical results that are sustained in patients with predominant acute soft disc prolapse generating medial nerve root compression or cord compression.

Degenerate-disc Infection Study with Contaminant Control: Discussion on the Research Methods.

OBJECTIVE: The role of bacterial infection in the causation of disc degeneration and its consequences is controversial. The current evidence is limited to underpowered studies, with the majority of such studies having only an internal contaminant arm, and only one study having a control arm with a non-degenerate disc population. The Degenerate-disc Infection Study with Contaminant Control (DISC) study includes a control arm and an internal contaminant control to resolve these shortcomings. METHODS: The study is designed as a case-control study: cases are patients undergoing surgery for degenerated disc pathology and controls are patients undergoing surgery for non-degenerate pathology, such as trauma, scoliosis or tumor cases. RESULTS: This study is part of a multi-centric trial involving six spine centers with 15 spine surgeons contributing. The DISC study methodology, rationale and controversies are presented here. The predominant issue is how to interpret contamination. We present our algorithm for the DISC study to address this. For disc samples that are positive concurrently with positive paraspinal tissue sample, the result will be interpreted as contamination. For positive disc samples with a negative paraspinal tissue culture result, the interpretation of this result will be infection. If cultures for both disc sample and paraspinal tissue sample are negative, then the result is interpreted as non-infected. If the disc culture is negative but paraspinal tissue culture is positive, then it is treated as a contaminant. CONCLUSIONS: Future large-scale studies are required with a good control arm, a contamination arm, and histopathological correlations.

Do intra-operative neurophysiological changes predict functional outcome following decompressive surgery for lumbar spinal stenosis? A prospective study.

BACKGROUND: To analyse the relation between immediate intraoperative neurophysiological changes during decompression and clinical outcome in a series of patients with lumbar spinal stenosis (LSS) undergoing surgery. METHODS: Twenty-four patients with neurogenic intermittent claudication (NIC) due to LSS undergoing decompressive surgery were prospectively studied. Intra operative trans-cranial motor evoked potentials (tcMEPs) were recorded before and immediately after surgical decompression. Lower limb normalised tcMEP improvement was used as primary neurophysiological outcome. Clinical outcome was assessed using the Zurich Claudication Questionnaire (ZCQ) self-assessment score, before surgery (baseline) and at an average of 8 and 29 months post-operatively. RESULTS: We found a moderate positive correlation between tcMEP changes and ZCQ at early follow-up (R=0.36). At late follow-up no correlation was found between intra-operative tcMEP and ZCQ changes. Dichotomizing the data showed a statistically significant relationship between tcMEP improvement and better functional outcome at early follow-up (P=0.013) but not at later follow-up (P=1). CONCLUSIONS: Our findings suggest that intra-operative neurophysiological improvement during decompressive surgery may predict a better clinical outcome at early follow-up although this is not applicable to late follow-up possibly due to the observed erosion of functional improvement with time.

Fusion Assessment by MRI in Comparison With CT in Anterior Lumbar Interbody Fusion: A Prospective Study.

STUDY DESIGN: Prospective cohort study. OBJECTIVES: To evaluate the role of magnetic resonance imaging (MRI) in evaluation of fusion status following anterior lumbar interbody fusion (ALIF) and compare agreement and confidence in assessing fusion or its absence on MRI to the current standard computed tomography (CT). METHODS: A prospective follow up of patients undergoing surgery by 2 spine surgeons between 2012 and 2015 at a single institution. Fusion was assessed at different time points in these patients by 2 independent musculoskeletal radiologists. Fusion was analyzed in coronal and sagittal planes using both imaging modalities, with confidence being attributed on a scale of 0 to 3. Assessors were blinded to patient data. RESULTS: Fourteen patients (25 levels) with mean follow-up of 10.2 months (range 2.4-20.3 years) and age of 41 years (range 20.7-61.5 years) were assessed. MRI within the interbody cage in coronal (κ = .58) and sagittal (κ = .50) planes had the highest interobserver agreement. CT anterior to the cage in coronal (κ = .48) and sagittal (κ = .44) planes, as well as within the cage in coronal (κ = .50) and sagittal planes (κ = .44) showed moderate agreement. Confidence anterior to the interbody cage using MRI scan was reduced when compared with remaining angles and imaging modalities. CONCLUSIONS: The study demonstrates that MRI may be a useful tool in the assessment of fusion following ALIF with results comparable to CT, and that it may have a useful role in select patients especially considering marked radiation exposure reduction.

Anterior Lumbar Interbody Fusion Using Reaction Bonded Silicon Nitride Implants: Long-Term Case Series of the First Synthetic Anterior Lumbar Interbody Fusion Spacer Implanted in Humans.

BACKGROUND: In this study, a historical case series is reported of reaction bonded silicon nitride (Si3N4) implants for anterior lumbar interbody fusion (ALIF) for a patient population of 30 and surgery levels L3/4, L4/5, and/or L5/S1. Before the study, the only work on Si3N4 as a biomedical material was associated preliminary work, which involved animal trials using a rabbit model. The objective was to undertake the first use of Si3N4 as a biomedical material for humans, as an implant for ALIF. METHODS: The Si3N4 implants were prepared by die-pressing silicon powder and reaction bonding in 95 N2/5 H2 at ∼1400°C for ∼50 hours. The surgeries involved a retroperitoneal approach for L3/4 and L4/5 levels and a transperitoneal approach for L5/S1 level. The patient follow-up involved assessment of radiologic fusion up to 30 years and clinical outcomes to 10 years. RESULTS: The reaction bonded Si3N4 implants were found to be biologically safe and to show high fusion rates with minimal subsidence, no abnormal reaction, and no other complications. The primary outcome measure, visual analog scale back pain, improved from a preoperative mean of 8.4 (range, 6-10) to a mean of 3.7 (range, 0-9) at 5 years and a mean of 4.9 (range, 0-9) at 10 years. The Oswestry Disability Index improved from a preoperative mean of 48 (range, 26-84) to a mean of 35 (range, 4-76) at 10 years. CONCLUSIONS: This study confirms that Si3N4 is biologically safe in the long-term, with capacity for excellent radiologic osseointegration.

Influence of Obesity on Complications, Clinical Outcome, and Subsidence After Anterior Lumbar Interbody Fusion (ALIF): Prospective Observational Study.

BACKGROUND: The complications associated with obesity have been well described for posterior lumbar spinal surgery. However, the influence of obesity on anterior lumbar interbody fusion (ALIF) is not well established. We aimed to compare complication risks, functional outcomes, and subsidence rates in normal-weight, overweight, and obese patients who underwent ALIF. METHODS: A total of 137 consecutive patients undergoing ALIF surgery from 2012 to 2014 were followed prospectively. Patients were categorized into 3 groups according to their body mass index (BMI). Patients were evaluated preoperative and postoperatively. Outcome measures included Short Form-12, Oswestry Disability Index, surgical complications, and subsidence. RESULTS: There was no significant difference between the BMI groups in terms of baseline age, proportion of men, levels operated, smoking status, diabetes status, or anterior, posterior, or average disc height. There was no difference in operative duration, blood loss, or hospital stay. At 12-month follow-up, no difference was found in terms of total complications, change in Short Form-12 mental or physical component scores, or Oswestry Disability Index scores. Average disc height was significant lower for the obese group (11.3 mm) compared with the normal-weight (14.4 mm) group. Fusion rate was also significantly lower for patients who were obese (60%) compared with normal-weight (88.2%) and overweight patients (76%) (P = 0.014). Delayed subsidence rates also were similar between normal-weight and overweight patients. CONCLUSIONS: There were no differences in functional outcomes or complications in patients with elevated BMI compared with normal-weight patients. Fusion rates were lower for patients were obese. Obesity should not be considered a contraindication to surgery in patients with appropriate indication to undergo ALIF.

Worker's Compensation Status and Outcomes Following Anterior Lumbar Interbody Fusion: Prospective Observational Study.

BACKGROUND: Anterior lumbar-interbody fusion (ALIF) is a commonly performed procedure for degenerative spinal disorders with reasonable clinical and safety outcomes, although there is limited evidence regarding the impact of ALIF in patients receiving worker's compensation (WC) compared with those without. The aim of our study is to identify whether WC status affects the clinical outcome and rates of complication following ALIF surgery in a prospective cohort. METHODS: We followed prospectively 114 consecutive patients undergoing ALIF surgery from 2012-2014. Patients were categorized into 2 groups: those with worker's compensation (WC) (n = 24) and those without (n = 90). Patients were evaluated preoperative and postoperatively. Outcome measures included Short Form-12 (SF-12), Oswestry Disability Index (ODI), surgical complications, and subsidence. RESULTS: In terms of baseline traits, the WC group had a significantly higher proportion of class III/IV obesity patients, who were younger (46.3 vs. 60.2 years) compared with non-WC. There were no significant differences in fusion rates or preoperative or postoperative disk height. No significant differences were found for hospital stay, blood loss, or operation duration. Similar rates of complications were found between WC versus non-WC cohorts. No significant difference was noted in clinical improvement between the 2 cohorts with SF-12 PCS, SF-12 MCS, or ODI (P = 0.232). No significant difference was found in the proportion of patients achieving minimal clinically important difference for SF-12 PCS/MCS or ODI. CONCLUSIONS: In our prospective cohort, there were no significant differences found between WC versus non-WC patients in terms of fusion rates, complications, clinical outcomes, or proportion of patients achieving minimal clinically important difference.

Interventions for Lumbar Synovial Facet Joint Cysts: A Comparison of Percutaneous, Surgical Decompression and Fusion Approaches.

OBJECTIVE: Facet joint cysts (FJCs) of the lumbar spine are an increasingly reported cause of radiculopathy, lower back pain, and neurologic deficits. Currently, there is a lack of conclusive evidence outlining when a particular treatment should be undertaken and what patient indications suit a particular approach. The present systematic review and meta-analysis aims to evaluate the efficacy of percutaneous treatment and surgical decompression with or without fusion. METHODS: A systematic literature search of scientific databases from their inception to February 2016 was performed by 2 reviewers. Studies pertaining to percutaneous procedures, decompressive surgeries, or decompressive surgeries with fusion for the treatment of lumbar facet joint cysts were identified. Data for resolution of symptoms, repeat procedures, and subsequent fusion were extracted and analyzed. RESULTS: Fifty studies comprising 870 patients with lumbar FJCs were identified for inclusion. Decompressive procedures were performed in 62.8% of patients, whereas 36.1% were treated by percutaneous aspiration or rupture, and only 1.1% were treated by decompression with fusion. Pooled analysis showed the rate of cyst resolution to be 90% for decompressive procedures with or without fusion and 58% for percutaneous procedures. Repeat procedures were required in 29% of percutaneous procedures, but less than 1% for all decompression operations. CONCLUSIONS: Evaluation of the literature shows surgical intervention to be advantageous over percutaneous procedures for the treatment of lumbar FJCs. There is no evidence suggesting when fusion should be undertaken because of the limited data available.

Subsidence following anterior lumbar interbody fusion (ALIF): a prospective study.

BACKGROUND: Anterior lumbar interbody fusion (ALIF) is a widely used surgical technique for disorders of the lumbar spine. One potential complication is the subsidence of disc height in the post-operative period. Few studies have reported the rate of subsidence in ALIF surgery prospectively. We prospectively evaluated the rate of subsidence in adult patients undergoing ALIF. METHODS: Results were obtained by reviewing scans of 147 patients. Disc heights were measured on radiographic scans taken pre-operatively in addition to post-operatively immediately, at 6 weeks and at 18 months. The anterior and posterior intervertebral disc heights were measured. Subsidence was defined as greater than or equal to 2 mm loss of height. RESULTS: A total of 15 patients (10.2%) had subsidence, with 7 being male. Each case was of delayed cage subsidence (DCS) >6 weeks postoperatively. The mean subsidence was 4.7 mm (range, 2.4-7.8). Mean anterior disc height was 8.6±0.4 mm preoperatively, which improved to 15.1±0.5 mm at latest follow-up. Mean posterior disc height was 4.7±0.2 mm preoperatively, which improved to 8.7±0.4 mm at latest follow-up. The mean lumbar lordosis (LL) angle was 42.5°±10.8° and the mean local disc angle (LDA) was 6.7°±4.0°. The 91.2% (n=114/125) of patients with appropriate radiological follow-up demonstrated fusion by latest follow-up. There was no correlation between subsidence rate with patient reported outcomes [Visual Analog Scale (VAS), Oswestry Disability Index (ODI) and Short Form 12 Item survey (SF-12)] and fusion rates. There was a significant negative correlation between LL and extent of subsidence (Pearson correlation =-0.754, P=0.012). CONCLUSIONS: In conclusion, we found that the subsidence rate at follow-up was generally low following standalone ALIF for this patient series. Patient clinical outcomes and bony fusion rates were not significantly influenced by subsidence.