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.

Biomechanical Analysis of 2 Versus 4 Rods Across the Cervicothoracic Junction in a Human Cadaveric Model.

BACKGROUND AND OBJECTIVES: Posterior reconstruction of the cervicothoracic junction poses significant biomechanical challenges secondary to transition from the mobile cervical to rigid thoracic spines and change in alignment from lordosis to kyphosis. After destabilization, the objectives of the current investigation were to compare the rod strain and multidirectional flexibility properties of the cervicothoracic junction using a 4-rod vs traditional 2-rod reconstructions. METHODS: Ten human cadaveric cervicothoracic specimens underwent multidirectional flexibility testing including flexion-extension, lateral bending, and axial rotation. After intact analysis, specimens were destabilized from C4 to T3 and instrumented from C3 to T4. The following reconstructions were tested: (1) 3.5-mm titanium (Ti) 2-rod, (2) 3.5-mm Ti 4-rod, (3) 4.0-mm cobalt chrome (CoCr) 2-rod, (4) 4.0-mm CoCr 4-rod, and (5) Ti 3.5- to 5.5-mm tapered rod reconstructions. The operative level range of motion and rod strain of the primary and accessory rods were quantified. RESULTS: The addition of accessory rods to a traditional 2-rod construct improved the biomechanical stability of the reconstructions in all three loading modalities for Ti ( P < .05). The accessory CoCr rods improved stability in flexion-extension and axial rotation ( P < .05). The addition of accessory rods in Ti or CoCr reconstructions did not significantly reduce rod strain ( P < .05). CoCr 2 and 4 rods exhibited less strain than both Ti 2 and 4 rods. CONCLUSION: Supplemental accessory rods affixed to traditional 2-rod constructs significantly improved stability of Ti alloys and CoCr alloy materials. The 4.0-mm CoCr rods provided greater stability than 3.5-mm Ti rods in flexion-extension, lateral bending, and axial rotation. While rod strain was not significantly reduced by the addition of accessory rods, it was reduced in CoCr rod treatment groups compared with the Ti rods.

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.

Dexamethasone and dexmedetomidine as adjuvants to ropivacaine do not prolong analgesia in wound infiltration for lumbar spinal fusion: a prospective randomized controlled study.

BACKGROUND AND OBJECTIVES: Local anesthetics (LAs) are widely used to infiltrate into surgical wounds for postoperative analgesia. Different adjuvants like dexamethasone and dexmedetomidine, when added to LA agents, could improve and prolong analgesia. The aim of this trial was to evaluate the analgesic efficacy and opioid-sparing properties of dexamethasone and dexmedetomidine when added to ropivacaine for wound infiltration in transforaminal lumbar interbody fusion (TLIF). METHODS: We conducted a controlled study among 68 adult patients undergoing TLIF, which was prospective, randomized and double-blind in nature. The participants were divided into four equal groups at random. Group R was given 150 mg of 1% ropivacaine (15 mL) and 15 mL of normal saline. Group R + DXM received 150 mg of 1% ropivacaine (15 mL) and 10 mg of dexamethasone (15 mL). Group R + DEX received 150 mg of 1% ropivacaine (15 mL) and 1 µg/kg of dexmedetomidine (15 mL). Lastly, group R + DXM + DEX was given 150 mg of 1% ropivacaine (15 mL), 10 mg of dexamethasone and 1 µg/kg of dexmedetomidine (15 mL). The primary focus was on the length of pain relief provided. Additionally, secondary evaluations included the amount of hydromorphone taken after surgery, the numerical rating scale and safety assessments within 48 h after the operation. RESULTS: Based on the p value (P > 0.05), there was no significant variance in the duration of pain relief or the total usage of hydromorphone after surgery across the four groups. Similarly, the numerical rating scale scores at rest and during activity at 6-, 12-, 24- and 48-h post-surgery for all four groups showed no difference (P > 0.05). However, the incidence of delayed anesthesia recovery was slightly higher in group R + DEX and group R + DXM + DEX when compared to group R or group R + DXM. Furthermore, there were no significant differences between the four groups in terms of vomiting, nausea, dizziness or delayed anesthesia recovery. CONCLUSION: For wound infiltration in TLIF, the addition of dexamethasone and dexmedetomidine to ropivacaine did not result in any clinically significant reduction in pain or opioid consumption and could prompt some side effects.

Mini-open Pedicle Subtraction Osteotomy versus Standard Posterior Approach for Ankylosing Spondylitis-related Spinal Kyphosis: A Comparative Study.

OBJECTIVE: Surgical strategy for spinal kyphosis in patients with ankylosing spondylitis (AS) has been challenging. Pedicle subtraction osteotomy (PSO) through a minimally invasive (MI) approach has been developed with promising clinical outcomes. We aimed to compare the effectiveness and safety of PSO via an MI approach and a standard posterior approach (SPA) for treating AS-related spinal kyphosis. METHODS: A total of 41 patients with AS-related spinal kyphosis who underwent PSO through an MI approach (MI surgery [MIS] group: n = 25) or SPA (SPA group: n = 16) between January 2015 and July 2020 were retrospectively included. Spinopelvic parameters were evaluated before the surgery, immediately after the surgery, and at the 2-year follow-up. Clinical data including operative time, estimated blood loss, blood transfusion, level of fusion, incision length, bed rest period, length of hospitalization, and surgical complications were compared between the two groups. The Scoliosis Research Society outcomes instrument-22 (SRS-22) was administered to assess patients' quality of life at the latest follow-up. Comparisons between the two groups were performed using independent sample t-test or Chi-square test. RESULTS: Characteristics and baseline kyphosis of the two groups were matched. At the 2-year follow-up, in the MIS group, the average correction values of the sagittal vertical axis and global kyphosis (GK) were 9.5 cm and 44.3°, respectively. Compared with the SPA group, the MIS group had similar correction values and correction losses after surgery. No obvious differences were observed in any radiographic parameters, except for GK, immediately after surgery and at the 2-year follow-up between the two groups (p > 0.05). The MIS group had a significantly shorter operative time, lesser blood loss, lesser transfusion volume, shorter fusion level, and lesser time to mobilization than did the SPA group. Higher average functional activity scores of SRS-22 were obtained in the MIS group than in the SPA group. CONCLUSION: Mini-open PSO may be an effective alternative to the SPA for treating AS-related spinal kyphosis, with comparable correction effect, lesser surgical trauma and faster recovery. This comparative study may provide valuable guidance for surgical decision-making and patient counseling.

[Analgesic effect of buccal acupuncture on patients after lumbar spinal fusion: a randomized controlled trial].

OBJECTIVE: To observe the effect of buccal acupuncture on pain after lumbar spinal fusion. METHODS: Sixty patients undergoing lumbar spinal fusion were randomly divided into an observation group (30 cases, 1 case dropped off) and a control group (30 cases, 1 case was eliminated). The patients in the control group were treated with routine anesthesia. On the basis of the control group, the patients in the observation group were treated with buccal acupuncture at bilateral back point, waist point, and sacral point for 30 min per treatment. The first acupuncture was given before anesthesia induction, and then once a day postoperation for two days, totally 3 treatments. The dosage of sufentanil, the number of remedial analgesia, and the incidence of nausea and vomiting within 48 h after surgery were compared between the two groups; rest and motion visual analogue scale (VAS) scores at 2 (T1), 8 (T2), 12 (T3), 24 (T4), and 48 (T5) h after surgery were observed; the quality of recovery-15 scale (QoR-15) at 24 and 48 h after surgery were evaluated. RESULTS: The dosage of sufentanil and the number of remedial analgesia within 48 h after surgery in the observation group were lower than those in the control group (P<0.01). There was no significant statistically difference in rest and motion VAS scores between the two groups in T1, T2, T3, T4 and T5 (P>0.05). The QoR-15 scores in the observation group at 24 and 48 h after surgery were higher than those in the control group (P<0.01). The incidence of nausea in the observation group was lower than that in the control group (P<0.05). CONCLUSION: Buccal acupuncture could reduce the amount of postoperative analgesic drugs of patients after lumbar spinal fusion, and promote early postoperative recovery.

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.

Systemic Diclofenac Sodium Reduces Postoperative rhBMP-2 Induced Neuroinflammation: A Rodent Model Study.

STUDY DESIGN: This is a basic science, animal research study. OBJECTIVE: This study aims to explore, in rodent models, the effectiveness of systemic nonsteroidal anti-inflammatory drugs in reducing recombinant human bone morphogenetic protein-2 (rhBMP-2) induced neuroinflammation. SUMMARY OF BACKGROUND DATA: rhBMP-2 is increasingly used to augment fusion in lumbar interbody fusion surgeries, although it can cause complications including postoperative radiculitis. MATERIALS AND METHODS: Eighteen 8-week-old Sprague-Dawley rats underwent Hargreaves testing to measure the baseline thermal withdrawal threshold before undergoing surgical intervention. The L5 nerve root was exposed and wrapped with an Absorbable Collagen Sponge containing rhBMP-2. Rats were randomized into 3 groups: (1) Low dose (LD), (2) high dose (HD) diclofenac sodium, and (3) saline, receiving daily injection treatment. Hargreaves testing was performed postoperatively on days 5 and 7. Seroma volumes were measured by aspiration and the nerve root was then harvested for hematoxylin and eosin, immunohistochemistry, Luxol Fast Blue staining, and real-time quantitative polymerase chain reaction. The Student t test was used to evaluate the statistical significance among groups. RESULTS: The intervention groups showed reduced seroma volume, and a general reduction of inflammatory markers (MMP12, MAPK6, GFAP, CD68, and IL18) compared with controls, with the reduction in MMP12 being statistically significant ( P = 0.02). Hematoxylin and eosin and immunohistochemistry of the nerve roots showed the highest macrophage density in the saline controls and the lowest in the HD group. Luxol Fast Blue staining showed the greatest extent of demyelination in the LD and saline groups. Lastly, Hargreaves testing, a functional measure of neuroinflammation, of the HD group demonstrated a minimal change in thermal withdrawal latency. In contrast, the thermal withdrawal latency of the LD and saline groups showed a statistically significant decrease of 35.2% and 28.0%, respectively ( P < 0.05). CONCLUSION: This is the first proof-of-concept study indicating that diclofenac sodium is effective in alleviating rhBMP-2-induced neuroinflammation. This can potentially impact the clinical management of rhBMP-2-induced radiculitis. It also presents a viable rodent model for evaluating the effectiveness of analgesics in reducing rhBMP-2-induced inflammation.

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.

Treatment of degenerative lumbar scoliosis using transforaminal lumbar interbody fusion based on the concept of intervertebral correction.

PURPOSE: The study aimed to examine the outcomes of posterior approach transforaminal lumbar interbody fusion (TLIF) in the treatment of degenerative lumbar scoliosis (DLS) based on the concept of intervertebral correction. METHODS: A retrospective analysis was performed on 76 surgical patients (36 males and 40 females) who underwent posterior TLIF and internal fixation based on the concept of intervertebral correction in Shenzhen Traditional Chinese Medicine Hospital from February 2014 to March 2021.The operation duration, intraoperative blood loss, incision length, and complications were recorded. Clinical efficacy was evaluated preoperatively and postoperative time points through the visual analog scale (VAS) and the Oswestry disability index (ODI). The changes in the coronal scoliosis curve (Cobb angle), coronal balance distance (CBD), the sagittal vertical axis (SVA), lumbar lordosis (LL), and pelvic tilt angle (PT) were assessed perioperatively at the last follow-up. RESULTS: All patients successfully underwent the operation. The average operation duration was 243.81 ± 35.35 (220 - 350) min; the average intraoperative blood loss was 836.27 ± 50.28 (700 - 2500) mL; the average incision length was 8.30 ± 2.33 (8 - 15) cm. The total complication rate was 18.42% (14/76). The VAS score of low back pain, lower extremity pain, and ODI score of patients at the last follow-up was significantly improved compared with those before the operation (P < 0.05). At the last follow-up, the Cobb Angle, CBD, SVA, and PT of patients were significantly lower than those before the operation (P < 0.05), and LL was higher than those before the operation (P < 0.05). CONCLUSION: TLIF based on the concept of intervertebral correction for the treatment of DLS may provide favourable clinical outcomes.

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.

The Effect of Adolescent Idiopathic Scoliosis on Natural Delivery and Epidural Use in Pregnant Females: A Matched Cohort Study.

STUDY DESIGN: Retrospective matched cohort study. OBJECTIVE: The aim of this study was to determine whether females with idiopathic scoliosis (IS), both with and without spine fusion, experience different rates of cesarean section (CS) and epidural anesthesia (EA) than females without scoliosis. SUMMARY OF BACKGROUND DATA: IS is a common spine condition with a higher prevalence in females. It is unclear whether females with scoliosis, treated nonoperatively or operatively, have different rates of cesarean delivery or EA. MATERIALS AND METHODS: Patients with IS who delivered in our integrated health care system during a 6-year period were identified (N = 1810). They were matched with a group without scoliosis who delivered during the same period (N = 1810). Rates and relative risk (RR) of CS and EA between cohorts and subgroups were calculated. RESULTS: The scoliosis cohort had significantly higher rates and RR of EA ( P = 0.002 and P = 0.004, respectively). Scoliosis patients treated nonoperatively had an 8% greater RR of EA ( P = 0.004) and had a significantly lower rate of CS (23.2% vs . 26%, P = 0.048) compared with the control group. Among only scoliosis patients, those treated with spine fusion had a 38% decreased RR of EA ( P < 0.001). Distal fusion level did not seem to influence the RR of EA or CS. CONCLUSIONS: Females with scoliosis were significantly more likely to receive EA at delivery compared with females without scoliosis. Rates and RR of cesarean delivery were not significantly lower among women with scoliosis, but females treated nonoperatively for scoliosis had a significantly lower CS rate than those without scoliosis. Females treated with spine fusion for scoliosis were far less likely to receive EA than both females without scoliosis and females with scoliosis treated nonoperatively.

Projected lifetime cancer risk for patients undergoing spine surgery for isthmic spondylolisthesis.

BACKGROUND CONTEXT: Radiographs, fluoroscopy, and computed tomography (CT) are increasingly utilized in the diagnosis and management of various spine pathologies. Such modalities utilize ionizing radiation, a known cause of carcinogenesis. While the radiation doses such studies confer has been investigated previously, it is less clear how such doses translate to projected cancer risks, which may be a more interpretable metric. PURPOSE: (1) Calculate the lifetime cancer risk and the relative contributions of preference-sensitive selection of imaging modalities associated with the surgical management of a common spine pathology, isthmic spondylolisthesis (IS); (2) Investigate whether the use of intraoperative CT, which is being more pervasively adopted, increases the risk of cancer. STUDY DESIGN/SETTING: Retrospective cross-sectional study carried out within a large integrated health care network. PATIENT SAMPLE: Adult patients who underwent surgical treatment of IS via lumbar fusion from January 2016 through December 2021. OUTCOME MEASURES: (1) Effective radiation dose and lifetime cancer risk associated with each exposure to ionizing radiation; (2) Difference in effective radiation dose (and lifetime cancer risk) among patients who received intraoperative CT compared to other intraoperative imaging techniques. METHODS: Baseline demographics and differences in surgical techniques were characterized. Radiation exposure data were collected from the 2-year period centered on the operative date. Projected risk of cancer from this radiation was calculated utilizing each patient's effective radiation dose in combination with age and sex. Generalized linear modeling was used to adjust for covariates when determining the comparative risk of intraoperative CT as compared to alternative imaging modalities. RESULTS: We included 151 patients in this cohort. The range in calculated cancer risk exclusively from IS management was 1.3-13 cases of cancer per 1,000 patients. During the intraoperative period, CT imaging was found to significantly increase radiation exposure as compared to alternate imaging modalities (adjusted risk difference (ARD) 12.33mSv; IQR 10.04, 14.63mSv; p<.001). For a standardized 40 to 49-year-old female, this projects to an additional 0.72 cases of cancer per 1,000. For the entire 2-year perioperative care episode, intraoperative CT as compared to other intraoperative imaging techniques was not found to increase total ionizing radiation exposure (ARD 9.49mSv; IQR -0.83, 19.81mSv; p=.072). The effect of intraoperative imaging choice was mitigated in part due to preoperative (ARD 13.1mSv, p<.001) and postoperative CTs (ARD 22.7mSv, p<.001). CONCLUSIONS: Preference-sensitive imaging decisions in the treatment of IS impart substantial cancer risk. Important drivers of radiation exposure exist in each phase of care, including intraoperative CT and/or CT scans during the perioperative period. Knowledge of these data warrant re-evaluation of current imaging protocols and suggest a need for the development of radiation-sensitive approaches to perioperative imaging.

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.