Ceramic substitutes, failure to achieve solid fusion in posterolateral instrumented fusion: a surgical and histological evaluation.

PURPOSE: As the number of instrumented fusions increases, so does the utilization of bone substitutes. However, controversies persist regarding the effectiveness of ceramics in promoting solid fusion. Few histological studies have been conducted on patients to address this issue. To contribute insights into this topic, we assessed bony fusion both intraoperatively and histologically in patients who underwent posterolateral instrumented fusions enhanced with a biphasic ceramic compound. METHODS: We analyzed a series of 13 patients who underwent revision surgery due to adjacent segment disease following the initial use of ceramics as bone extenders in the index surgery. In each case, patients exhibited apparent radiological fusion in the instrumented posterolateral fusions. Follow-up exceeded 18 months. Bone fusion was assessed intraoperatively, and biopsies of the bone mass at the intertransverse area were examined under an optical microscope. RESULTS: Surgical exploration of the fusion block at the intertransverse space did not indicate solid fusion. Moreover, histological analysis of the 13 biopsies revealed a lack of proper integration of the bone substitutes, incomplete resorption of hydroxyapatite granules, and substitution of ceramic particles by immature fibrous tissue lacking the structural competence to bear loads or add stability to spinal fusion. CONCLUSION: The utilization of biphasic ceramics proved ineffective in attaining a proper fusion mass between the intertransverse space. Both surgical inspection and histological studies confirmed the absence of integration. Prudence should be exercised regarding the use of ceramics. While no clear instability was observed, neither was there any integration.

Comparison of Surgical Site Infection After Instrumented Spine Surgery in Patients With High Risk of Infection According to Different Antibiotic Prophylaxis Protocols: A Cohort Study of 132 Patients With a Minimum Follow-Up of 1 year.

STUDY DESIGN: Observational Study. OBJECTIVES: Surgical site infections (SSIs) are one of the major complications in spine surgery. Numerous factors that increase the risk of SSI have been widely described. However, clinical guidelines on antibiotic prophylaxis are usually common for all patients. There are no specific guidelines for patients with a high risk of infection. The aim of this paper is to create a specific protocol for patients at high risk of SSI. METHODS: This is a three-cohort study using a prospective database. Risk patients are those who meet at least two of the following criteria: obesity, diabetes, reoperation and immunosuppression. Between October 2021 and April 2023, 132 patients were recruited.They were divided into three cohorts: cohort A, 46 patients, standard prophylaxis with cefazolin 2 g/8 h for 24 h; cohort B, 46 patients, cefazolin 2 g/8h and amikacin 500 mg/12 h for 24 h; cohort C, 40 patients, cefazolin 2 g/8h and amikacin 500 mg/12 h for 72 h. RESULTS: There was a significant decrease in the infection rate depending on the prophylaxis (23.9% in cohort A, 8.7% in cohort B, and 2.5% in cohort C). When logistic regression models were applied and cohorts B and C were compared with A, the following results were obtained: OR of 0.30 (CI: 0.08 - 0.97; P = 0.057) and 0.08 (IC: 0.00 - 0.45; P = 0.019), respectively. CONCLUSIONS: Prophylaxis with prolonged double antibiotic therapy with cefazolin and amikacin is associated with a statistically significant decrease in the rate of SSI in patients with a high risk of infection.

Instrumented lumbar fusion in patients over 75 years of age: is it worthwhile?-a comparative study of the improvement in quality of life between elderly and young patients.

Background: Surgical treatment of degenerative lumbar disease in the elderly is controversial. Elderly patients have an increased risk for medical and surgical complications commensurate with their comorbidities, and concerns over complications have led to frequent cases of insufficient decompression to avoid the need for instrumentation. The purpose of this study was to evaluate clinical outcome between older and younger patients undergoing lumbar instrumented arthrodesis. Methods: This is a retrospective, comparative study of prospectively collected outcomes. One hundred and fifty-four patients underwent 1- or 2-level posterolateral lumbar fusion. Patients were divided into two groups. Group 1: 87 patients ≤65 years of age who underwent decompression and posterolateral instrumented fusion; Group 2: 67 patients ≥75 years of age who underwent the same procedures with polymethylmethacrylate (PMMA) pedicle-screw augmentation. Mean follow-up 27.47 months (range, 76-24 months). Results: Mean age was 49.1 years old (range, 24-65) for the younger group and 77.8 (range, 75-86) in the elderly group. Patients ≥75 years of age showed higher preoperative comorbidity (American Society of Anesthesiology, ASA: 1.7 vs. 2.4), and ≥2 systemic diseases with greater frequency (12.5% vs. 44.7%). No significant differences were found between the two groups in terms of postoperative complications, fusion, or revision rate. During follow-up, adjacent disc disease and adjacent fracture occurred significantly more in Group 2 (P<0.05). At the end of follow-up, there were no significant differences between the two groups in any of the clinical and health-related quality of life scores or satisfaction with treatment received. Conclusions: Osteoporosis represents a major consideration before performing spine surgery. Despite an obvious increased risk of complications in elderly patients, PMMA-augmented fenestrated pedicle screw instrumentation in spine fusion represents a safe and effective surgical treatment option to elderly patients with poor bone quality. Age itself should not be considered a contraindication in otherwise appropriately selected patients.

Surgical Site Infection After Polymethyl Methacrylate Pedicle Screw Augmentation in Osteoporotic Spinal Vertebrae: A Series of 537 Cases.

BACKGROUND: Retrospective observational study of prospectively collected outcomes. OBJECTIVE: The use of transpedicular screws augmented with polymethyl methacrylate (PMMA) is an alternative for patients with osteoporotic vertebrae. To investigate whether using PMMA-augmented screws in patients undergoing elective instrumented spinal fusion (ISF) is correlated with an increased risk of infection and the long-term survival of these spinal implants after surgical site infection (SSI). METHODS: We studied 537 consecutive patients who underwent ISF at some point within a 9-year period, involving a total of 2930 PMMA-augmented screws. Patients were classified into groups: (1) those whose infection was cured with irrigation, surgical debridement, and antibiotic treatment; (2) those whose infection was cured by hardware removal or replacement; and (3) those in whom treatment failed. RESULTS: Twenty eight of the 537 patients (5.2%) developed SSI after ISF. An SSI developed after primary surgery in 19 patients (4.6%) and after revision surgery in 9 (7.25%). Eleven patients (39.3%) were infected with gram-positive bacteria, 7 (25%) with gram-negative bacteria, and 10 (35.7%) with multiple pathogens. By 2 years after surgery, infection had been cured in 23 patients (82.15%). Although there were no statistically significant differences in infection incidence between preoperative diagnoses (P = 0.178), the need to remove hardware for infection control was almost 80% lower in patients with degenerative disease. All screws were safely explanted while vertebral integrity was maintained. PMMA was not removed, and no recementing was done for new screws. CONCLUSIONS: The success rate for treatment of deep infection after cemented spinal arthrodesis is high. Infection rate findings and the most commonly found pathogens do not differ between cemented and noncemented fusion. It does not appear that the use of PMMA in cementing vertebrae plays a pivotal role in the development of SSIs.

Presence of Tumor Necrosis Factor-Alpha in Urine Samples of Patients With Chronic Low Back Pain Undergoing Chiropractic Care: Preliminary Findings From a Prospective Cohort Study.

Background and aims: Low back pain is the leading cause of years lived with disability worldwide. Chiropractors employ different interventions to treat low back pain, including spinal manipulative therapy, although the mechanisms through which chiropractic care improves low back pain are still unclear. Clinical research and animal models suggest that spinal manipulation might modulate plasma levels of inflammatory cytokines, which have been involved in different stages of low back pain. More specifically, serum levels of Tumor Necrosis Factor-alpha (TNF-α) have been found to be elevated in patients with chronic low back pain. We aimed to investigate whether urine from chronic low back pain patients could be an appropriate medium to measure concentrations of TNF-α and to examine possible changes in its levels associated to chiropractic care. Methods: Urine samples were collected from 24 patients with chronic low back pain and TNF-α levels were analyzed by ELISA before and after 4-6 weeks of care compared to a reference value obtained from 5 healthy control subjects, by means of a Welch's t-test. Simultaneously, pain intensity and disability were also evaluated before and after care. Paired t-tests were used to compare mean pre and post urinary concentrations of TNF-α and clinical outcomes. Results: Significantly higher baseline levels of urinary TNF-α were observed in chronic low back pain patients when compared to our reference value (p < 0.001), which were significantly lower after the period of chiropractic treatment (p = 0.03). Moreover, these changes were accompanied by a significant reduction in pain and disability (both p < 0.001). However, levels of urinary TNF-α were not correlated with pain intensity nor disability. Conclusion: These results suggest that urine could be a good milieu to assess TNF-α changes, with potential clinical implications for the management of chronic low back pain.

Anterior 1-2 Level Cervical Corpectomy and Fusion for Degenerative Cervical Disease: A Retrospective Study With Lordotic Porous Tantalum Cages. Long-Term Changes in Sagittal Alignment and Their Clinical and Radiological Implications After Cage Subsidence.

BACKGROUND: Despite the advances in anterior cervical corpectomy and fusion (ACCF) as a reconstructive surgical technique, the rate of complications related to artificial implants remains high. The purpose of this study was to investigate the long-term clinical course of ACCF with tantalum trabecular metal (TTM)-lordotic implants. Focus is placed on the relevance and influence of implant subsidence on sagittal alignment and the related clinical implications. METHODS: Retrospective, observational study of prospectively collected outcomes including 56 consecutive patients with degenerative cervical disc disease (myelopathy and/or radiculopathy). All patients underwent 1-level or 2-level ACCF with TTM-lordotic implants. The mean duration of follow-up was 4.85 years. RESULTS: The fusion rate at the end of follow-up was 98.11% (52/53). Implant subsidence occurred in 44 (83.01%) cases, including slight subsistence (<3 mm) in 37 (69.81%) and severe subsidence (>3 mm) in 7 cases (13.2%). The greatest degree of subsidence developed in the first 3 months postoperatively (P = 0.003). No patients presented a significant increase in implant subsidence beyond the second year of follow-up. The most common site of severe subsidence was the anterior region of the cranial end plate (4/7). At the end of follow-up, C1-C7 lordosis and segmental-Cobb angle of the fused segment increased on average by 5.06 ± 8.26 and 1.98 ± 6.02 degrees, respectively, though this difference failed to reach statistical significance (P > 0.05). Visual analog scale and Neck Disability Index scores improved at the conclusion of follow-up (P < 0.05). CONCLUSIONS: ACCF with anterior cervical reconstruction using TTM-lordotic implants and anterior cervical plating for treatment of cervical degenerative disease has high fusion rates and good clinical outcome. The osteoconductive properties of TTM provide immediate stabilization and eliminate the need for bone grafts to ensure solid bone fusion. Before fusion occurs, asymptomatic implant settlement into the vertebral body is inevitable. However, lack of parallelism and reduced contact surface between the implant and the vertebral end plate are major risk factors for severe further subsidence, which may negatively affect the clinical outcomes.

Simplified Pedicle Subtraction Osteotomy for Osteoporotic Vertebral Fractures.

BACKGROUND: In osteoporotic vertebral fractures (OVF) involving neurological symptoms and severe kyphosis, vertebral osteotomies are necessary but are associated with a high risk of complications. METHODS: We performed a retrospective study. In 14 patients (mean age, 69.3 years old) with unstable thoracolumbar fractures associated with severe kyphosis, a posterior instrumentation with polymethylmethacrylate-augmented screws and a modified pedicle subtraction osteotomy (PSO) at the fracture level were performed to stabilize the spine and correct the kyphosis. The underlying principle behind the osteotomy's technique was to exaggerate the defect caused by the fracture and shorten the spine: (1) completion of a wide laminoforaminotomy, (2) use of successive reamers rotated in the pedicle at a 25° angle in the axial plane to obtain its complete decancellation, (3) insertion of the reamers in a more medial orientation (55°) to collapse the posterior wall, and (4) breakage of the lateral wall. Radiographic and clinical outcomes were analyzed pre- and postoperatively. Complications were reported. RESULTS: Functional scores improved after surgery. Oswestry disability index and visual analog scale scores decreased significantly (33 and 4 points, respectively). Patient satisfaction rate reached 93%. Average postoperative regional vertebral kyphosis was decreased to 3.79°. No dural tear or neurological injuries were observed. Blood loss of 920 mL (±350 mL) and two mechanical complications were reported. CONCLUSIONS: OVF can lead to severe deformities. In osteoporotic bones, the use of sequential reamers can simplify the PSO technique, allowing for the shortening and stabilization of the spine without manipulating the dural sac. The risk of neurological injuries and blood loss is decreased. LEVEL OF EVIDENCE: 4.

Lung injury in patients age 75 years and older with the use of polymethylmethacrylate fenestrated pedicle screws.

BACKGROUND CONTEXT: Pulmonary complications in patients age 75 years and older who undergo spinal fusion may have catastrophic consequences. The use of augmentation techniques with polymethylmethacrylate (PMMA) have been associated with pulmonary damage. The use of fenestrated pedicle screws augmented with PMMA may increase the risk of lung injury in this population. PURPOSE: To investigate whether the use of PMMA-augmented screws is correlated with increased lung injury in patients undergoing instrumented lumbar spinal fusion. STUDY DESIGN: A nonrandomized, prospective, case-controlled clinical study was carried out. PATIENT SAMPLE: We included 50 consecutive patients: 25 classifieds as patients who required PMMA-augmented screws in lumbar spinal fusion, and 25 classifieds as control participants because they underwent uncemented instrumented spinal fusion. OUTCOME MEASURES: We compare the incidence of the event, lung damage, in both groups by measuring a series of parameters: arterial blood gas, transesophageal echocardiography, urinary desmosine, and chest radiograph. The epidemiological parameters analyzed were age, sex, body mass index, status as a smoker, and number of cement leaks. METHODS: Changes in pulmonary damage markers were described in both groups of patients, comparing postsurgery values with baseline values. In control participants, each change was evaluated for the total number of patients. All changes are indicated in this report by mean differences for quantitative variables and by differing proportions for qualitative variables, with 95% confidence intervals provided for all values. RESULTS: There was an increase in postinstrumentation PaO2 (arterial partial pressure of oxygen) in both groups, probably related to the use of mechanical ventilation and recruitment maneuvers. Even though the group that required augmentation had lower baseline levels, the difference between groups was not statistically significant. On transesophageal echocardiographs, we observed scattered small, snowflake-like emboli, and bright echo signals appeared in the right atrium during PMMA injection. Signal density was constant but gradually faded away when PMMA injection ended. No participants in the group without augmentation had radiological complications. Overall, desmosine levels increased in both groups, and the rise was similar in both. There was a slight average increase in urine desmosine levels after instrumentation and progressively continues to rise until 24 hours after instrumentation, with a subsequent decrease at 72 hours. Comparing the two groups, we found no statistically significant differences at any time. CONCLUSIONS: We were not able to identify a significant difference in urine desmosine levels associated with the augmentation of with fenestrated pedicle screws with PMMA. Despite comparing patients age 75 years or older with a younger group, we found no clinical, analytical, or gasometric data indicating lung damage in patients who had augmentation.

Safety and Efficacy With Augmented Second-Generation Perforated Pedicle Screws in Treating Degenerative Spine Disease in Elderly Population.

BACKGROUND: Degenerative spine disease is a common cause of low back pain in people age 65 years or older. Nonsurgical treatment is tried first, but if it is unsuccessful, surgery is advocated. This has special connotations for both underlying disease and the biomechanical characteristics of osteoporotic bone. We conducted an observational study to investigate the clinical and radiological outcome in patients in this age group with poor bone quality and degenerative lumbar instability treated with fusion using perforated pedicle screws augmented with polymethylmethacrylate (PMMA). METHODS: We collected prospective data on treatment, outcome, and patient characteristics from our institution's database. The primary outcome was a change in pain and physical function measured by the visual analog scale, the Core Outcome Measures Index, and the Oswestry Disability Index. Control participants were also analyzed for secondary complications such as hardware mobilization, fusion (as apparent on radiographs), and adjacent fractures or adjacent degenerative disc disease. RESULTS: We included 89 patients who underwent surgery between October 2015 and February 2018 at a mean age of 78 years (range, 67-88 years) and were then monitored for at least 12 months (range, 12-40 months). Findings on pain and function questionnaires showed improvement at 6 months after surgery, maintained at the final evaluation; 90% of patients had final score increases of ≥15 points. No patient developed clinical complications secondary to PMMA leakages. One patient had nonunion and screw breakage. No other patient had clinical or radiological nonunion. Of the control participants, 6 had adjacent disc disease, with 2 of them requiring instrumentation extension. Six deep infections required surgical revision without removal of material. CONCLUSION: PMMA-augmented cannulated pedicle screw instrumentation in spine fusion effectively and safely treats degenerative lumbar disease in patients who are age 65 years or older with poor bone quality.

Comparative study of the effects of osteoprotegerin and testosterone on bone quality in male orchidectomised rats.

Aim: The aim of this work is to compare the effects of osteoprotegerin (OPG) and testosterone on bone quality in a model of orchidectomised (ORX) rats.Methods: Three-month-old ORX or SHAM operated groups (n = 15 each group) were used. The SHAM and ORX groups received saline. There were two ORX groups, receiving OPG-Fc (10 mg/kg twice weekly) (ORX + OPG-Fc) or testosterone cypionate (1.7 mg/kg/weekly) for 8 weeks. After sacrifice, bone analysis by femoral and lumbar dual-energy X-ray absorptiometry and micro-computed tomography in femora were performed. Histological sections of vertebrae were dyed with hematoxylin-eosin or safranin. Serum osteocalcin (BGP), total alkaline phosphatase (ALP), and C-terminal telopeptide of type I collagen (CTX) were analyzed.Results: ORX resulted in femoral and vertebral bone loss and in microarchitectural deterioration. Treatment with OPG-Fc and testosterone recovered lumbar (L) and femoral (F) bone mineral densitometry bone mineral density (BMD) to SHAM levels. Femoral BMD was significantly higher after treatment with OPG-Fc than after testosterone treatment due to the presence of osteopetrotic changes in the metaphyseal region of long bones. Serum levels of ALP and CTX increased, while OPG levels were unchanged in ORX rats. Treatment with OPG-Fc decreased the levels of BGP, ALP, and CTX. Treatment with testosterone maintained biochemical markers of bone turnover at levels similar to or higher than those of ORX rats.

Spinal fusion achieves similar two-year improvement in HRQoL as total hip and total knee replacement. A prospective, multicentric and observational study.

INTRODUCTION: Total hip and knee arthroplasty (THA/TKA) are surgical procedures with proven benefits. Although the literature reports outcomes of fusion of the lumbar spine comparable to those of THA/TKA in general health-related quality-of-life (HRQoL) questionnaires, functional assessment is nevertheless needed for these results to be of use in clinical practice and management. Aim of our study was to prove that lumbar spinal fusion has similar if not better outcomes than THA/TKA using intervention-specific HRQoL questionnaires and functional assessment questionnaires. MATERIALS AND METHODS: Observational, ambispective, multicentre study of three cohorts undergoing lumbar spinal fusion (n = 115), THA (n = 119) and TKA (n = 253). Patients were evaluated using the Short-Form-12 (SF-12), Harris-Hip-Score, Hospital for Special Surgery Scale (HSS) and Oswestry Low Back Pain Disability questionnaires. A minimum follow-up of two years was conducted. RESULTS: The SF-12 showed significant improvement in all groups. The SF-12 physical component summary score indicated a more severe pre-operative status (p = 0.031) in the THA cohort. The mental component summary score indicated a less severe pre-operative status in the TKA cohort (p = 0.008) and greater post-operative improvement in the TKA and THA cohorts across follow-up (six months p = 0.021; one year p = 0.012; two years p = 0.042). Functional assessment indicated greater pre-operative disability in the THA group. At two years of follow-up, functional improvement according to the Harris, HSS and Oswestry questionnaires were 152.01%, 50.07% and 41.14% respectively. CONCLUSIONS: This study demonstrates that lumbar spinal fusion and total knee and hip arthroplasty are comparable in terms of functional improvement when thoroughly studied with health, quality-of-life and functional assessment questionnaires.

Osteoporosis and the Management of Spinal Degenerative Disease (I).

Osteoporosis has become a major medical problem as the aged population of the world rapidly grows. Osteoporosis predisposes patients to fracture, progressive spinal deformities, and stenosis, and is subject to be a major concern before performing spine surgery, especially with bone fusions and instrumentation. Osteoporosis has often been considered a contraindication for spinal surgery, while in some instances patients have undergone limited and inadequate procedures in order to avoid concomitant instrumentation. As the population ages and the expectations of older patients increase, the demand for surgical treatment in older patients with osteoporosis and spinal degenerative diseases becomes progressively more important. Nowadays, advances in surgical and anesthetic technology make it possible to operate successfully on elderly patients who no longer accept disabling physical conditions. This article discusses the biomechanics of the osteoporotic spine, the diagnosis and management of osteoporotic patients with spinal conditions, as well as the novel treatments, recommendations, surgical indications, strategies and instrumentation in patients with osteoporosis who need spine operations.