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.

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.

Analysis of bone cement distribution around fenestrated pedicle screws in low bone quality lumbosacral vertebrae.

PURPOSE: To study the exact distribution of bone cement around augmented fenestrated pedicle screws in both lumbar and sacral vertebrae of patients with low bone quality. METHODS: A total of 37 patients with instrumented lumbar fusion were investigated. 3D computed tomography virtual models of the injected cement and screws were obtained. The models were computed for their centroid (i.e. their average mass centre point), and their coordinates (x, y, z) were projected on their respective screw-transversal and screw-longitudinal planes for further analysis. RESULTS: The results showed better bone cement homogeneous distribution around the screws in lumbar (L4 and L5) than in sacral (S1) vertebrae. In the lumbar region, the centroids were transversally projected near the transversal centre of symmetry of the screws. On the other hand, in the sacral region, the cement flowed preferentially outside the centre of symmetry of the screws, into the sacral ala. CONCLUSIONS: The results confirm the different flow behaviours of bone cement in lumbar versus sacra vertebrae. The computer methodology followed in this study helps to understand the clinical monitoring observations and lays the foundations for better positioning of the screws and specific vertebrae-oriented screw designs.