Risk Factors of Hidden Blood Loss in Unilateral Biportal Endoscopic Surgery for Patients with Lumbar Spinal Stenosis.

OBJECTIVE: Unilateral biportal endoscopic (UBE) surgery has recently been used as a minimally invasive procedure for the treatment of lumbar spinal stenosis and is associated with less perioperative blood loss. However, perioperative hidden blood loss (HBL) may be neglected during UBE. This study aimed to examine the volume of HBL and discuss the influential risk factors for HBL during unilateral biportal endoscopic surgery. METHODS: From January 2022 to August 2022, 51 patients underwent percutaneous unilateral biportal endoscopic surgery for lumbar spinal stenosis at the Department of Spinal Surgery of the Affiliated Traditional Chinese Medicine Hospital of Southwest Medical University and were enrolled in this study. The data included general indicators (age, sex and body mass index [BMI]), underlying disease (hypertension and diabetes), laboratory test results (prothrombin time [PT], activated partial thromboplastin time [APTT], fibrinogen [Fbg]), and preoperative and postoperative hematocrit and hemoglobin), related imaging parameters (severity of intervertebral disc [IVD] degeneration and soft tissue thickness of the interlaminar approach), number of operated vertebrae and operation time. Total blood loss (TBL) and HBL during surgical procedures were measured via the Gross formula. Influential factors were further analyzed by multivariate linear regression analysis and t-tests. RESULTS: The mean HBL was 257.89 ± 190.66 mL for single-operation patients and 296.58 ± 269.75 mL for two-operation patients. Patients with lower PT (p = 0.044), deeper tissue thickness (p = 0.047), and diabetes mellitus were determined to have more HBL during UBE. The operation time might also be an important factor (p = 0.047). However, sex (p = 0.265), age (p = 0.771/0.624), BMI (p = 0.655/0.664), APTT (p = 0.545/0.751), degree of degenerated IVD (p = 0.932/0.477), and hypertension (p = 0.356/0.896) were not related to HBL. CONCLUSION: This study determined the different influential factors of HBL during UBE. PT, tissue thickness, and diabetes mellitus are the independent risk factors that affect HBL incidence. Long PT may decrease the volume of HBL within a certain range. Tissue thickness and diabetes mellitus can lead to an increased volume of HBL.

Comparison of the mid-term clinical efficacy of different fixtaion methods combined with oblique lumbar interbody fusion in treating lumbar degenerative diseases.

BACKGROUND: To compare the mid-term follow-up clinical efficacy among three treatment approaches for lumbar degenerative diseases (LDD): standalone oblique lumbar interbody fusion (SF), oblique lumbar interbody fusion combined with lateral screw fixation (LF), and oblique lumbar interbody fusion combined with posterior screw fixation (PF). METHOD: This retrospective study included a total of 71 cases of single level LDD that underwent OLIF in Hospital of Chengdu University of Traditional Chinese Medicine were retrospectively collected between March 2016 and September 2017. Patients were divided into three groups: 24 cases in the SF group, 24 cases in the LF group and 23 cases in the PF group. Various parameters, such as operation time, hospitalization time, and complications, were recorded. The fusion condition was assessed at last follow up. Clinical outcomes were evaluated using the Visual Analogue Scale (VAS) and Oswestry Disability Index (ODI) from pre-operation to 5 years post-surgery. RESULTS: Significantly lower mean operation time and hospitalization time were observed in the SF and LF groups compared to the PF group (p < .05). However, no significant difference in fusion rate was found among the three groups. Regarding clinical outcomes, there was no statistically significant difference in VAS scores between the three groups during all follow-up periods. At the 6th month and 1st year after surgery, the SF and LF groups had significantly lower Oswestry Disability Index (ODI) scores compared to the PF group (p < .05). There was no significant difference in perioperative complication rates among the three groups (p > .05). In the LF group, one case of instrument displacement and urethra injury were reported, while in the SF, LF, and PF groups, 10, 9, and 3 cases of cage subsidence were reported, respectively. CONCLUSION: The study findings suggest that oblique lumbar interbody fusion (OLIF) is a safe and effective treatment for mid-term management of lumbar degenerative diseases (LDD). Compared to the posterior screw fixation (PF) group, both the standalone OLIF (SF) and OLIF combined with lateral screw fixation (LF) groups showed advantages in terms of reduced operation time, shorter hospitalization, and faster symptom alleviation in the short-term. However, OLIF combined with PF demonstrated comparable symptom relief in the mid-term and had the additional benefit of lower cage subsidence rates while improving fusion rates as well.

Clinical Study of Percutaneous Endoscopic Large-channel Fusion and Transforaminal Lumbar Interbody Fusion in the Treatment of Degenerative Lumbar Spinal Stenosis.

Context: Degenerative changes in the lumbar spine more commonly cause spinal stenosis and with the aging of society, its incidence is on the rise. Endoscopic spinal surgery is a minimally invasive technique for decompression. The efficacy of percutaneous, endoscopic, large-channel fusion and transforaminal lumbar interbody fusion (TLIF) need confirmation by more studies. Objective: The study intended to investigate the clinical efficacy of percutaneous endoscopic large-channel fusion and TLIF in the treatment of degenerative lumbar spinal stenosis, to find the best treatment plan. Design: The research team performed a retrospective study. Setting: The study took place at Nanjing Lishui People's Hospital in Nanjing, Jiangsu Province, PR China. Participants: Participants were 100 patients with degenerative, lumbar, spinal stenosis who had been admitted to the hospital between October 2018 and October 2022. Intervention: The research team randomly divided participants into an intervention group and a control group, with 50 participants in each group. The intervention group received percutaneous, endoscopic, large-channel fusion and internal fixation, and the control group received foraminal, lumbar, interbody fusion. Outcome Measures: The research team measured: (1) perioperative indexes, (2) clinical efficacy at a postoperative follow-up at 6 months postintervention, (3) indexes for inflammatory responses at baseline and postintervention, (4) postoperative pain at baseline and at months 3 and 6 postintervention using a visual analog scale (VAS), (6) lumbar function at baseline and months 3 and 6 postintervention using the Oswestry Disability Index (ODI) and the Japanese Orthopedic Association (JOA) scale, and (7) complications. Results: Compared with the control group, the intervention group's perioperatively related and inflammatory-response indexes were significantly better: (1) amount of bleeding- 112.67 ± 17.38 for the control group and 78.62 ± 10.52 for the intervention group (P = .002); (2) volume of drainage-79.63 ± 14.21 for the control group and 52.18 ± 8.21 for the intervention group (P = .001); (3) ESR at baseline and postintervention-22.41 ± 5.62 and 15.18 ± 5.26, respectively, for the control group and 22.58 ± 5.82 and 10.54 ± 3.18, respectively, for the intervention group, with P = .013 postintervention; and (4) CRP at baseline and postintervention-17.42 ± 3.52 and 13.98 ± 3.65 for the control group, respectively, and 18.65 ± 3.78 and 10.14 ± 2.78 for the intervention group, with P = .008 postintervention; Also, compared to the control group, the intervention group's: (1) total effective rate was significantly higher (P = .018); (2) incidence of postoperative complications was significantly lower (P = .006); (3) VAS pain score was significantly lower at months 3 and 6, with P = .028 and P = .021, respectively; (4) Oswestry Disability Index (ODI) function score was significantly lower at months 3 and 6, with P = .016 and P = .014, respectively; and (5) postoperative JOA function score was significantly higher at months 3 and 6, with P = .011 and P = .007, respectively. Conclusions: Both percutaneous, endoscopic, large-channel fusion and TLIF had good therapeutic effects in the treatment of degenerative lumbar spinal stenosis. However, compared with the latter, the former was more effective, with better comprehensive efficacy and more obvious benefits for patients, so it's worthy of clinical promotion and use.

High Cell Saver Autotransfusion is Associated With Perioperative Medical Complications in Adult Spinal Deformity Patients.

STUDY DESIGN: A retrospective, propensity-matched observational study. OBJECTIVE: To assess the impact of cell saver (CS) homologous transfusion on perioperative medical complications in adult patients undergoing spinal deformity surgery. SUMMARY OF BACKGROUND DATA: Despite many endorsing its use, many analyses still refute the efficacy of CS on decreasing total perioperative allogenic red blood cell transfusions, cost efficiency, and its effect on perioperative complications. METHODS: Adult patients who underwent spinal deformity surgery at a single center between 2015 and 2021 were retrospectively reviewed. Patient-specific, operative, radiographic, and 30-day complications/readmission data were collected for further analysis. Two methods were utilized to test our hypothesis: (1) absolute threshold model: two cohorts created among patients who received ≥550 mL of CS intraoperatively and those who received less; (2) adjusted ratio model: two cohorts created dependent on the ratio of CS to estimated blood loss (EBL). Propensity-score matching and various statistical tests were utilized to test the association between CS and perioperative medical complications. RESULTS: Two hundred seventy-eight patients were included in this analysis with a mean age of 61.3±15.7yrs and 67.6% being female. Using the first method, 73 patients received ≥550 mL of CS, and 205 received less. Propensity-score matching resulted in 28 pairs of patients. 39.3% of patients with ≥550 mL CS required readmission within 30 days compared with 3.57% of patients in the <550 mL cohort ( P =0.016), despite a nearly identical proportion of patients requiring intraoperative blood transfusions ( P >0.9999). Using the second method, 155 patients had CS/EBL<0.33 and 123 with CS/EBL ≥0.33. 5.16% and 21.9% among patients with CS/EBL<0.33 and CS/EBL≥0.33, respectively, were readmitted by the 30-day marker ( P <0.0001). CONCLUSIONS: Our findings indicate that greater CS volumes transfused are associated with higher rates of 30-day readmissions. Thus, surgeons should consider limiting CS volume intraoperatively to 550 mL and when greater volumes are required or preferred, ensuring that the ratio of CS:EBL remains under 0.33.

Interbody Cage Placement Without Plate Supplementation Adjacent to Plated Segments in Multilevel Anterior Cervical Decompression and Fusion.

STUDY DESIGN: A retrospective cohort study. OBJECTIVE: To evaluate the clinical efficacy and safety of hybrid anterior cervical fixation, focusing on stand-alone segments. SUMMARY OF BACKGROUND DATA: In the treatment of multilevel cervical stenosis, the number of segments fixed using a plate is limited by placing an interbody cage without plate supplementation at one end of the surgical segment to reduce long plate-related problems. However, the stand-alone segment may experience cage extrusion, subsidence, cervical alignment deterioration, and nonunion. METHODS: Patients who underwent three-segment or four-segment fixation for cervical degenerative disease and completed one-year follow-up were included in this study. Patients were divided into two groups: a cranial group, with stand-alone segments located at the cranial end adjacent to plated segments, and a caudal group, with stand-alone segments located at the caudal end. Differences in radiographic outcomes between the groups were evaluated. Fusion was defined using dynamic radiographs or computed tomography. To identify factors associated with nonunion in stand-alone segments, multivariable logistic regression analyses were performed. To identify factors associated with cage subsidence, multiple regression analyses were performed. RESULTS: A total of 116 patients (mean age, 59±11 y; 72% male; mean fixed segments, 3.7±0.5 segments) were included in this study. No case showed cage extrusion or plate dislodgement. In stand-alone segments, the fusion rate was significantly lower in the caudal group than in the cranial group (76% vs. 93%, P =0.019). Change in the cervical sagittal vertical axis was worse in the caudal group than in the cranial group (2.7±12.3 mm vs. -2.7±8.1 mm, P =0.006). One caudal group patient required additional surgery because of nonunion at the stand-alone segment. Multivariable logistic regression indicated factors associated with nonunion included the location of the stand-alone segment (caudal end: OR 4.67, 95% CI, 1.29-16.90), larger pre-disk space range of motion (OR 1.15, 95% CI, 1.04-1.27), and lower preoperative disk space height (OR 0.57, 95% CI, 0.37-0.87). Multiple regression analysis indicated that higher cage height and lower pre-disk space height were associated with cage subsidence. CONCLUSION: Hybrid anterior cervical fixation with stand-alone interbody cage placement adjacent to plated segments may avoid long plate-related problems. Our results suggest that the cranial end of the construct may be more suitable for the stand-alone segment than the caudal end.

Can anterior vertebral body tethering provide superior range of motion outcomes compared to posterior spinal fusion in adolescent idiopathic scoliosis? A systematic review.

PURPOSE: Anterior vertebral body tethering (AVBT) was introduced as a fusionless alternative to treating adolescent idiopathic scoliosis (AIS) while preserving range of motion (ROM). This is the first systematic review to compare the ROM outcomes between AVBT and PSF in treating AIS. METHODS: We conducted a comprehensive search on PubMed, EMBASE, MEDLINE, and Cochrane Library. Inclusion criteria were patients with AIS treated with AVBT or PSF or both, and clearly defined ROM outcomes; exclusion criteria were scoliosis other than AIS, biomechanical or cadaveric studies, non-English publications, case reports, conference summaries, unpublished literature, commentaries, and reviews. Primary outcome was ROM. Secondary outcomes included Cobb angle correction, quality of life (QOL), complications, and muscle strength and endurance. RESULTS: Twelve studies were included in this review. We found moderate evidence to support that AVBT results in superior ROM outcomes than PSF while achieving comparable Cobb angle correction with low evidence. The comparison of QOL outcomes between AVBT and PSF remained inconclusive. In addition to the complications noted conventionally in PSF, AVBT could result in over-correction and distal adding-on. We also found very low evidence to support that AIS patients treated with AVBT have superior muscle strength and endurance when compared to those treated with PSF. CONCLUSIONS: AVBT provides better preservation of ROM and muscle strength postoperatively when compared with PSF, while achieving comparable curve correction. Future studies should explore the spinal growth trajectory to determine the window of opportunity for AVBT in AIS.

Creation and preclinical evaluation of a novel mussel-inspired, biomimetic, bioactive bone graft scaffold: direct comparison with Infuse bone graft using a rat model of spinal fusion.

OBJECTIVE: Infuse bone graft is a widely used osteoinductive adjuvant; however, the simple collagen sponge scaffold used in the implant has minimal inherent osteoinductive properties and poorly controls the delivery of the adsorbed recombinant human bone morphogenetic protein-2 (rhBMP-2). In this study, the authors sought to create a novel bone graft substitute material that overcomes the limitations of Infuse and compare the ability of this material with that of Infuse to facilitate union following spine surgery in a clinically translatable rat model of spinal fusion. METHODS: The authors created a polydopamine (PDA)-infused, porous, homogeneously dispersed solid mixture of extracellular matrix and calcium phosphates (BioMim-PDA) and then compared the efficacy of this material directly with Infuse in the setting of different concentrations of rhBMP-2 using a rat model of spinal fusion. Sixty male Sprague Dawley rats were randomly assigned to each of six equal groups: 1) collagen + 0.2 µg rhBMP-2/side, 2) BioMim-PDA + 0.2 µg rhBMP-2/side, 3) collagen + 2.0 µg rhBMP-2/side, 4) BioMim-PDA + 2.0 µg rhBMP-2/side, 5) collagen + 20 µg rhBMP-2/side, and 6) BioMim-PDA + 20 µg rhBMP-2/side. All animals underwent posterolateral intertransverse process fusion at L4-5 using the assigned bone graft. Animals were euthanized 8 weeks postoperatively, and their lumbar spines were analyzed via microcomputed tomography (µCT) and histology. Spinal fusion was defined as continuous bridging bone bilaterally across the fusion site evaluated via µCT. RESULTS: The fusion rate was 100% in all groups except group 1 (70%) and group 4 (90%). Use of BioMim-PDA with 0.2 µg rhBMP-2 led to significantly greater results for bone volume (BV), percentage BV, and trabecular number, as well as significantly smaller trabecular separation, compared with the use of the collagen sponge with 2.0 µg rhBMP-2. The same results were observed when the use of BioMim-PDA with 2.0 µg rhBMP-2 was compared with the use of the collagen sponge with 20 µg rhBMP-2. CONCLUSIONS: Implantation of rhBMP-2-adsorbed BioMim-PDA scaffolds resulted in BV and bone quality superior to that afforded by treatment with rhBMP-2 concentrations 10-fold higher implanted on a conventional collagen sponge. Using BioMim-PDA (vs a collagen sponge) for rhBMP-2 delivery could significantly lower the amount of rhBMP-2 required for successful bone grafting clinically, improving device safety and decreasing costs.

Comparison of 270-degree percutaneous transforaminal endoscopic decompression under local anesthesia and minimally invasive transforaminal lumbar interbody fusion in the treatment of geriatric lateral recess stenosis associated with degenerative lumbar spondylolisthesis.

PURPOSE: Various lumbar decompression techniques have been used for the treatment of degenerative lumbar spondylolisthesis (DLS). Few studies have compared the clinical efficacy of percutaneous transforaminal endoscopic decompression (PTED) and minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF) in the treatment of lateral recess stenosis associated with DLS (LRS-DLS) in geriatric patients. The objective of the study was to compare the safety and short-term clinical efficacy of 270-degree PTED under local anesthesia and MIS-TLIF in the treatment of LRS-DLS in Chinese geriatric patients over 60 years old. MATERIALS AND METHODS: From January 2017 to August 2019, the data of 90 consecutive geriatric patients with single-level L4-5 LRS-DLS were retrospectively reviewed, including those in the PTED group (n = 44) and MIS-TLIF group (n = 46). The patients were followed up for at least 1 year. Patient demographics and perioperative outcomes were reviewed before and after surgery. The Oswestry Disability Index (ODI), visual analog scale (VAS) for leg pain, and modified MacNab criteria were used to evaluate the clinical outcomes. X-ray examinations were performed 1 year after surgery to assess the progression of spondylolisthesis in the PTED group and bone fusion in the MIS-TLIF group. RESULTS: The mean patient ages in the PTED and MIS-TLIF groups were 70.3 years and 68.6 years, respectively. Both the PTED and MIS-TLIF groups demonstrated significant improvements in the VAS score for leg pain and ODI score, and no significant differences were found between the groups at any time point (P > 0.05). Although the good-to-excellent rate of the modified MacNab criteria in the PTED group was similar to that in the MIS-TLIF group (90.9% vs. 91.3%, P > 0.05), PTED was advantageous in terms of the operative time, estimated blood loss, incision length, drainage time, drainage volume, length of hospital stay, and complications. CONCLUSIONS: Both PTED and MIS-TLIF led to favorable outcomes in geriatric patients with LRS-DLS. In addition, PTED caused less severe trauma and fewer complications. In terms of perioperative quality-of-life and clinical outcomes, PTED could supplement MIS-TLIF in geriatric patients with LRS-DLS.

Intraoperative CT for lumbar fusion is not associated with improved short- or long-term complication profiles.

BACKGROUND CONTEXT: The use of intraoperative CT has continued to grow in recent years, as various techniques leverage the promise of improved instrumentation accuracy and the hope for decreased complications. Nonetheless, the literature regarding the short- and long-term complications associated with such techniques remains scant and/or confounded by indication and selection bias. PURPOSE: To use causal inference techniques to determine whether intraoperative CT use is associated with an improved complication profile as compared to conventional radiography for single-level lumbar fusions, an increasingly commonplace application for this technology. STUDY DESIGN/SETTING: Inverse probability weighted retrospective cohort study carried out within a large integrated health care network. PATIENT SAMPLE: Adult patients who underwent surgical treatment of spondylolisthesis via lumbar fusion from January 2016 to December 2021. OUTCOME MEASURES: Our primary outcome was the incidence rate of revision surgery. Our secondary outcome was the incidence of composite 90-day complications (deep and superficial surgical site infection, venous thromboembolic events, and unplanned readmissions). METHODS: Demographics, intraoperative information, and postoperative complications were abstracted from electronic health records. A propensity score was developed utilizing a parsimonious model to account for covariate interaction with our primary predictor, intraoperative imaging technique. This propensity score was utilized in the creation of inverse probability weights to adjust for indication and selection bias. The rate of revisions within 3 years as well as the rate of revisions at any time-point were compared between cohorts using Cox regression analysis. The incidence of composite 90-day complications were compared using negative binomial regression. RESULTS: Our patient population consisted of 583 patients, with 132 who underwent intraoperative CT and 451 who underwent conventional radiographic techniques. There were no significant differences between cohorts following inverse probability weighting. No significant differences were detected in 3-year revision rates (HR, 0.74 [95% CI 0.29, 1.92]; p=.5), overall revision rates (HR, 0.54 [95% CI 0.20, 1.46]; p=.2), or 90-day complications (RC -0.24 [95% CI -1.35, 0.87]; p=.7). CONCLUSIONS: Intraoperative CT use was not associated with an improved complication profile in either the short- or long-term for patients undergoing single-level instrumented fusion. This observed clinical equipoise should be weighed against resource and radiation-related costs when considering intraoperative CT for low complexity fusions.

Do Adolescent Idiopathic Scoliosis Patients With Vitamin D Deficiency Have Worse Spine Fusion Outcomes?

BACKGROUND: Prior research has shown that patients with adolescent idiopathic scoliosis (AIS) have a higher prevalence of vitamin D deficiency compared with healthy peers. In adult orthopaedic populations, vitamin D deficiency has been shown to be a risk factor for higher reported pain and lower function. We investigated whether there was an association between vitamin D levels and AIS patient-reported outcomes, as measured by the Scoliosis Research Society (SRS-30) questionnaire. METHODS: This was a single-center, cross-sectional study. Postoperative AIS patients were prospectively recruited during routine follow-up visits, 2 to 10 years after spine fusion. Vitamin D levels were measured by serum 25-hydroxyvitamin D (ng/mL). Patients were categorized based on vitamin D level: deficient (<20 ng/mL), insufficient (20 to 29 ng/mL), or sufficient (≥30 ng/mL). The correlation between vitamin D levels and SRS-30 scores was analyzed using multivariable analysis and pair-wise comparisons using Tukey method. RESULTS: Eighty-seven AIS patients (83% female) were enrolled who presented at median 3 years (interquartile range: 2 to 5 y; range: 2 to 10 y) after spine fusion. Age at time of surgery was mean 15 (SD±2) years. Major coronal curves were a mean of 57 (SD±8) degrees preoperatively and 18 (SD±7) degrees postoperatively. It was found that 30 (34%) of patients were vitamin D sufficient, 33 (38%) were insufficient, and 24 (28%) were deficient. Although there was no correlation between vitamin D level and Pain, Mental Health, or Satisfaction domains ( P >0.05), vitamin D-deficient patients were found to be younger ( P <0.001) and had lower SRS-30 function ( P =0.002), Self-image ( P <0.001), and total scores ( P =0.003). CONCLUSIONS: AIS patients with vitamin D deficiency (<20 ng/mL) are more likely to be younger age at time of surgery, and report lower Function, Self-image, and Total SRS-30 scores postoperatively. Further work is needed to determine whether vitamin D supplementation alters curve progression and patient outcomes. LEVEL OF EVIDENCE: Level II-prognostic study.

A triple minimally invasive surgery combination for subacute osteoporotic lower lumbar vertebral collapse with neurological compromise: a potential alternative to the vertebral corpectomy/expandable cage strategy.

OBJECTIVE: Acute/subacute osteoporotic vertebral collapses (OVCs) in the lower lumbar spine with neurological compromise, although far less well documented than those in the thoracolumbar junction, may often pose greater treatment challenges. The authors clarified the utility of 3 familiar combined techniques of minimally invasive surgery for this condition as an alternative to the corpectomy/expandable cage strategy. METHODS: This report included the authors' first 5 patients with more than 2 years (range 27-48 months) of follow-up. The patients were between 68 and 91 years of age, and had subacute painful L4 OVC with neurological compromise and preexisting lumbar spinal stenosis. The authors' single-stage minimally invasive surgery combination consisted of the following: step 1, balloon kyphoplasty for the L4 OVC to restore its strength, followed by L4-percutaneous pedicle screw (PPS) placement with patients in the prone position; step 2, tubular lateral lumbar interbody fusion (LLIF) at the adjacent disc space involved with endplate injury, with patients in the lateral position; and step 3, supplemental PPS-rod fixation with patients in the prone position. RESULTS: Estimated blood loss ranged from 20 to 72 mL. Neither balloon kyphoplasty-related nor LLIF-related potentially serious complications occurred. With CT measurements at the 9 LLIF levels, the postoperative increases averaged 3.5 mm in disc height and 3.7 mm in bilateral foraminal heights, which decreased by only 0.2 mm and 0 mm at the latest evaluation despite their low bone mineral densities, with a T-score of -3.8 to -2.6 SD. Canal compromise by fracture retropulsion decreased from 33% to 23% on average. As indicated by MRI measurements, the dural sac progressively enlarged and the ligamentum flavum increasingly shrank over time postoperatively, consistent with functional improvements assessed by the physician-based, patient-centered measures. CONCLUSIONS: The advantages of this method over the corpectomy/expandable cage strategy include the following: 1) better anterior column stability with a segmentally placed cage, which reduces stress concentration at the cage footplate-endplate interface as an important benefit for patients with low bone mineral density; 2) indirect decompression through ligamentotaxis caused by whole-segment spine lengthening with LLIF, pushing back both the retropulsed fragments and the disc bulge anteriorly and unbuckling the ligamentum flavum to diminish its volume posteriorly; and 3) eliminating the need for segmental vessel management and easily bleeding direct decompressions. The authors' recent procedural modification eliminated step 3 by performing loose PPS-rod connections in step 1 and their tight locking after LLIF in step 2, reducing to only once the number of times the patient was repositioned.

Percutaneous carbon-PEEK instrumentation for spine tumors: a prospective observational study.

BACKGROUND: Minimally invasive spine surgery (MISS) has been progressively accepted as a useful approach for spine tumors. Recently released carbon-PEEK implants have been already reported as effective in open surgeries for spine tumors. This study aimed to evaluate the feasibility, surgical, clinical and radiological outcomes of a new percutaneous carbon-PEEK instrumentations for spine tumors. METHODS: This is a prospective case-control observational study. Demographical, clinical, surgical, and radiological data were collected from May 2018 to August 2019. Visual Analogue Scale for back pain (VAS), the Oswestry Disability Index (ODI) Questionnaire, EORTC QLQ-C30 questionnaire for quality of life, and ASIA Impairment Scale (AIS) were collected before surgery and at 6 weeks and follow-up (FU) visits. Data were compared with the control group, a retrospective series of 23 metastatic patients that underwent titanium pedicle screw fixation. RESULTS: Twenty-one patients met inclusion criteria. Mean age was 59.2 years (range, 35-78) and mean FU was 14.2 months (7-22). Thoracic spine was involved in 14 (66.7%) cases, lumbar spine in 7 (33.3%). The mean length of surgery was 75 (42-185) minutes, mean blood loss was 90ml (50-215) and every patient was mobilized within 24 hours after surgery. The VAS (8.3±1.1 to 2.9±1.0, P<0.05) and ODI (54.6±11.7 to 25.1±5.4, P<0.05) scores significantly improved over follow-up. AIS improved in 7 (33.3%) patients and remained unchanged in 14 (66.7%). The EORTC QLQ-C30 global health/QoL, functional and symptomatic scales significantly improved postoperatively and at the last follow-up. Only two minor complications (9.5%) were recorded. No statistically significant difference was observed between the two groups related to clinical, radiological outcomes, complications rate and implant failure. CONCLUSIONS: Percutaneous Carbon/PEEK implants could be considered as alternative to standard titanium implants in oncological patients, according to their lower rate of MRI artifacts, facilitating radiological FU and adjuvant radiotherapy. Further clinical trials and biomechanical evaluations are needed to confirm our preliminary results.

Aspergillus terreus spondylodiscitis following acupuncture and acupotomy in an immunocompetent host: case report and literature review.

Aspergillus terreus is a fungus responsible for various infections in human beings; however, spine involvement is uncommon. Herein, we report a case of A. terreus spondylodiscitis following acupuncture and acupotomy in an immunocompetent Chinese patient. Admission lumbar magnetic resonance imaging (MRI) revealed infection at the L4/5 level without significant vertebral destruction. After unsuccessful symptomatic and anti-tuberculosis treatments, A. terreus was identified through culture, microscopy of isolate, histological examination and VITEK system. Intravenous voriconazole was then given; however, the patient's spinal condition deteriorated rapidly, resulting in evident destruction of the L4/5 vertebral bodies. Surgeries including L4/5 intervertebral disc debridement, spinal canal decompression, posterior lumbar interbody fusion (PLIF) with allogeneic fibula ring fusion cages, and posterior pedicle screw fixation were then performed. Imaging findings at one-month and six-month follow-up suggested that the patient was successfully treated. This case highlighted two important points: firstly, although acupuncture and acupotomy are generally regarded as safe conservative treatments for pain management, they can still lead to complications such as fungal spinal infection. Therefore, vigilance is necessary when considering these treatments; secondly, PLIF with allogeneic fibula ring fusion cages may be beneficial for A. terreus spondylodiscitis patients with spinal instability.

Intraoperative Electromyography in Awake Minimally Invasive Transforaminal Lumbar Interbody Fusion: A Case Study on Nerve Activation Under the Effects of Local Anesthesia.

SUMMARY: With the versatility of lumbar spine surgery continually expanding, intraoperative electromyography (EMG) has become a common adjunct used to reduce risk of nerve injury and postoperative neurologic deficit. EMG monitoring has been deemed particularly useful in the minimally invasive transforaminal lumbar interbody fusion. A more recent evolution of the minimally invasive transforaminal lumbar interbody fusion entails complete percutaneous access to the disc through Kambin's triangle, followed by a percutaneous lumbar interbody fusion. Given the lack of direct visualization of nervous structures with percutaneous entrance into the disc, there is risk of injury to surrounding nervous structures with this approach. In effort to reduce risk of nerve injury, application of triggered EMG to gauge proximity of nervous tissue has been evaluated. Recently, patients presenting with contraindications or concerns for general anesthesia have been offered the alternative to undergo their procedure with spinal anesthesia, allowing them to remain awake. Spinal anesthesia entails intrathecal administration of local anesthetic, which mechanistically acts to reduce overall excitability of surrounding neural structures. However, nerve activation under conditions of local anesthetic is relatively unknown, and the ability of triggered EMG monitoring to reliably detect nerve proximity becomes questionable. This case report demonstrates nerve activation at thresholds comparable with those seen under general anesthesia. Although this has sparked interest in the possibility that local anesthetic may not remarkably affect nerve excitability as measured by triggered EMG activation, further investigation is recommended to reliably apply triggered EMG monitoring in awake spine surgery.

Effects of rhBMP-2-loaded hydroxyapatite granules/beta-tricalcium phosphate hydrogel (HA/ß-TCP/hydrogel) composite on a rat model of caudal intervertebral fusion.

The effects and inflammation-related side effects of bone morphogenetic protein (BMP)-2 on posterior lumbar interbody fusion are controversial. One of the potential causes for the inconsistent results is the uncontrolled release of BMP-2 from the collagen carrier. Therefore, BMP delivery systems that support effective bone regeneration while attenuating the side effects are strongly sought for. We developed NOVOSIS putty (NP), a novel composite material of hydroxyapatite (HA), beta-tricalcium phosphate (ß-TCP)/hydrogel, and BMP-2, which can sustainably release BMP-2 over 2 weeks. This study was aimed at comparing the effects and side effects of NP and collagen sponge (CS) containing BMP-2 using a rat caudal intervertebral fusion model. The fusion rates of NP with low and high doses of BMP-2 were significantly higher than those of an iliac bone (IB) graft, but those of CS with low and high doses of BMP-2 were not different from those of the IB graft. Furthermore, the incidences of ectopic bone formation and soft tissue swelling were significantly lower in the NP group than in the CS group. The HA/ß-TCP/hydrogel carrier enabled superior bone induction with low-dose BMP-2 and decreased the incidence of side effects caused by high-dose BMP-2 vis-à-vis the collagen carrier.

Poor Bone Quality, Multilevel Surgery, and Narrow and Tall Cages Are Associated with Intraoperative Endplate Injuries and Late-onset Cage Subsidence in Lateral Lumbar Interbody Fusion: A Systematic Review.

BACKGROUND: A major complication of lateral lumbar interbody fusion (LLIF) is cage subsidence, which may lead to clinical problems, including loss of disc height correction, altered spinal alignment, recurrent pain, and vertebral body fracture. A thorough review of the current knowledge about the risk factors for the two types of cage subsidence after LLIF-intraoperative endplate injury and late-onset cage subsidence-could bring attention to well-established risk factors for clinical consideration while identifying any incompletely characterized factors that require further research to clarify. QUESTIONS/PURPOSES: We performed a systematic review to answer the following questions: (1) Are bone quality and surrogates for bone quality, such as patient age and sex, associated with an increased likelihood of cage subsidence? (2) Are implant-related factors associated with an increased likelihood of cage subsidence? METHODS: Two independent reviewers comprehensively searched Medline, Embase, Cochrane Library, PubMed, and Web of Science from 1997 to 2020 to identify all potential risk factors for cage subsidence after LLIF. Discrepancies were settled through discussion during full-text screening. Search terms included "lateral" AND "interbody fusion" AND "subsidence" OR "settling" OR "endplate injury" OR "endplate violation" WITHOUT "cervical" OR "transforaminal" OR "biomechanical." Eligible studies were retrospective or prospective comparative studies, randomized controlled trials, and case series with sample sizes of 10 patients or more reporting risk factors for cage subsidence or endplate injury after LLIF. Studies that involved cervical interbody fusions and biomechanical and cadaveric experiments were excluded. The Grading of Recommendations Assessment, Development, and Evaluation (GRADE) approach was used to assess the studies' quality of evidence. The initial database review found 400 articles. Thirty-four articles with moderate- to very-low-quality evidence met the inclusion criteria for analysis. A total of 3233 patients (58% [1860] of whom were female) were included in this review. Two types of cage subsidence were reviewed: late-onset cage subsidence, which occurs gradually postoperatively, and intraoperative endplate injury, which is derived from iatrogenic endplate violation during endplate preparation or cage insertion. Among 20 studies with moderate quality of evidence according to the GRADE criteria, eight studies reported risk factors for cage subsidence related to bone mineral density and its surrogates and 12 studies focused on risk factors regarding implant factors, including cage dimension, cage material, construct length, and supplementary instrumentation. RESULTS: Patients with a dual x-ray absorptiometry T-score of -1.0 or less, age older than 65 years, and female sex were considered to have a high risk of both types of cage subsidence. Regarding cage size, cage width ≥ 22 mm helped to avoid late-onset cage subsidence, and cage height ≤ 11 mm was recommended by some studies to avoid intraoperative endplate injuries. Studies recommended that multilevel LLIF should be conducted with extra caution because of a high risk of losing the effect of indirect decompression. Studies found that standalone LLIF might be sufficient for patients without osteoporosis or obesity, and supplementary instrumentation should be considered to maintain the postoperative disc height and prevent subsidence progression in patients with multiple risk factors. The effect of the bone graft, cage material, endplate condition, and supplementary instrumentation on cage subsidence remained vague or controversial. CONCLUSION: Patients with poor bone density, patients who are older than 65 years, and female patients should be counseled about their high risk of developing cage subsidence. Surgeons should avoid narrow cages when performing LLIF to minimize the risk of late-onset cage subsidence, while being cautious of an aggressive attempt to restore disc height with a tall cage as it may lead to intraoperative endplate injury. For multilevel constructs, direct decompression approaches, such as posterior and transforaminal LIF, should be considered before LLIF, since the effect of indirect decompression may be difficult to maintain in multilevel LLIF because of high risks of cage subsidence. The effect of the cage material and supplementary instrumentation require stronger evidence from prospectively designed studies with larger sample size that randomly assign patients to polyetheretherketone (PEEK) or titanium cages and different fixation types. Future research on intraoperative endplate injuries should focus on the specific timing of when endplate violation occurs with the help of intraoperative imaging so that attempts can be made to minimize its occurrence. LEVEL OF EVIDENCE: Level IV, therapeutic study.

Severe complications and management of a patient with myasthenia gravis undergoing anterior cervical spinal surgery: a case report.

Surgical management of patients with comorbid long-term myasthenia gravis (MG) is particularly challenging and MG thus represents an independent risk factor for perioperative complications. However, few studies have reported on the perioperative assessment, prevention measures, and risks in MG patients undergoing major surgery, especially for anterior cervical spine surgery. We herein report the rare case of a 62-year-old man with a 20-year history of MG, who was admitted to our hospital with diagnosis of degenerative cervical spondylosis. He safely underwent anterior cervical corpectomy of C4, discectomy of C5-6, and fusion of C3-6. Intraoperative motor evoked potential was recorded to detect significant improvement after decompression. However, the patient suffered from progressive dysphagia, bucking, and hyperpyrexia 20 days after the initial operation. Imaging revealed titanium cage sliding and graft dislodgement. Secondary surgery was performed for posterior internal fixation from C2-7 and anterior revision from C3-6 after Halo-Vest traction, antibiotic treatment, and immunoglobulin therapy. He underwent a series of postoperative treatments, including cervicothoracolumbosacral orthosis, atomization inhalation, chest physiotherapy, antibiotics, and nutritional support. His condition improved markedly and he had no recurrence of symptoms during the 6-month follow-up. It is the rare reported case of anterior cervical spinal surgery in a patient with MG. This rare case indicates a relative contraindication to anterior-only approaches especially with multiple levels for MG patients with cervical spondylosis. Posterior approach, intraoperative monitoring, osteoporosis, postoperative strong brace protection, and supportive management should be considered for patients who were on large doses of steroids for long duration of time, given the lack of sufficient bone mineral density.

Optimizing Lumbar Pedicle Screw Trajectory Utilizing a 3D-Printed Drill Guide to Ensure Placement of Pedicle Screws Into Higher Density Bone May Improve Pedicle Screw Pullout Resistance.

BACKGROUND: Lower preoperative Hounsfield Unit (HU) values of vertebral body are associated with pedicle screw (PS) loosening after implantation with traditional trans-pedicular trajectory. However, the relationship between trajectory HU value and PS fixation quality remains unknown. This study aimed to investigate if 3-dimensionally (3D)-printed guider directed accurate implantation of pedicle screw could increase the anti-pulling properties of screws. METHODS: 3D models of cadaveric spines were reconstructed by using computed tomography image and PS trajectories were designed for both sides of vertebra. The designed trajectories were divided into high HU group and low HU group. PS implantation with 3D-printed screw guide can be in complementary shape with target vertebra. Throughout 3D finite element analysis and biomechanical tests, the pull-out strength of screws in high or low trajectory HU groups were compared. RESULTS: The HU value was 132 ± 13 (mean ± standard deviation) in low HU group and 189 ± 17 in high HU group. The distance between planned trajectories and actual trajectories was 1.69 ± 0.4 mm. Biomechanical tests showed that in the high trajectory HU group the pull-out strength of screws was 750.41 ± 80.65 N; compared with 655.83 ± 74.31 N in the low trajectory HU group, the difference was statistically significant. When simulated with the finite element method, the pull-out strength of low HU trajectory pedicle screws was lower than that of high HU trajectory pedicle screws. CONCLUSIONS: Preoperative computer-assisted trajectory design using a 3D-printed screw guide may direct more accurate implantation with optimal implantation trajectory, and may provide a new way to improve pedicle screw fixation.

Cervical balance and clinical outcomes in cervical spondylotic myelopathy treated by three-level anterior cervical discectomy and fusion and hybrid cervical surgery: A CONSORT-compliant study with minimum follow-up period of 5 years.

ABSTRACT: As the technology of combining with fusion and nonfusion procedure, cervical hybrid surgery (HS) is an efficacious alternative for treatment with cervical spondylotic myelopathy. While studies on cervical alignment between 3-level HS and anterior cervical discectomy and fusion (ACDF) were seldom reported. The effects of cervical imbalance on its related clinical outcomes are yet undetermined as well.Patients with cervical spondylotic myelopathy, who underwent 3-level ACDF or HS, were included to compare cervical alignment parameters after surgery and then explore the relationship between cervical balance and clinical outcomes.Forty-one patients with HS (HS group) and 32 patients who with ACDF (ACDF group) were reviewed from February 2007 to September 2013 with the mean follow-up of 90.3 ±â€Š25.5 (m) and 86.3 ±â€Š28.9 (m), respectively. Cervical alignments parameters including the C2 to C7 cervical lordosis (CL), C2 to C7 sagittal vertical axis, T1 slope. and T1SCL (T1 slope minus CL), and the clinical outcomes like neck disability index (NDI) and Japanese Orthopedic Association (JOA) score were measured and recorded preoperatively (PreOP), intraoperatively, and on the first preoperative day and the last follow-up (FFU). The balance and imbalance groupings were sorted based on the T1SCL: T1SCL≤20°,balance; T1SCL > 20°, imbalance.We found significant improvements (P < .001) in NDI and JOA at intraoperatively and FFU after ACDF and HS, and no difference on cervical alignment and clinical outcomes between the 2 procedures on the basis of intergroup comparisons. By between-subgroups comparisons, however, we found significant differences in CL and T1SCL at PreOP (P < .05). Nonetheless, there was no significant difference on the clinical outcomes between balance and imbalance subgroups at FFU at PreOP (P > .05), indicating that the change of T1SCL was not correlated to NDI and JOA at FFU.Both HS and ACDF groups showed significant clinical improvements after surgery. There was no correlation between cervical balance and clinical symptoms.

Utilization, Utility, and Variability in Usage of Adjunctive Hyperbaric Oxygen Therapy in Spinal Management: A Review of the Literature.

The objective of this review was to understand the clinical utilization, utility, and variability in the usage of adjunctive hyperbaric oxygen therapy (HBOT). Surgical site infection is associated with high morbidity and mortality, increased health care expenditure, and decreased quality of life. With the increasing prevalence of adult spinal deformity and spinal fusion surgery, it is imperative to understand the potential benefits of adjunctive treatments. HBOT is a safe and common procedure indicated to treat various medical conditions. We conducted a literature search across 3 databases for English articles published between December 1, 2019 and December 1, 2000. Thirteen studies were included. HBOT may lessen the duration of antimicrobial therapy and mitigate instrument removal and revision surgery. The current usage indications for HBOT are supported by level III evidence for chronic osteomyelitis and level IV evidence for osteoradionecrosis. However, the same level of evidence exists to support the beneficial use of adjunctive HBOT for noncomplicated spinal infections within 2 months after surgery. When cultured, the most common organisms were Staphylococcus aureus and other low-virulence organisms. The most common treatment protocol consists of 90-minute sessions of 100% Fio2 at 2-3 atmosphere absolute with a mean of 35.3 ± 11.6 sessions for 5.2 ± 1.4 weeks. Adjunctive HBOT should be considered in select high-risk patients. Further improvements in diagnosis and categorization of spinal infections are necessary and will indelibly aid the decision making for the initiation of HBOT.