Clarke, Michelle J.

OBJECTIVE Lordotic devices have garnered increased attention for improving the segmental lordosis (SL) achieved with transforaminal lumbar interbody fusion (TLIF). However, it is unclear the degree to which surgeons maximize the "ideal" or listed lordosis of the interbody device. METHODS Patients undergoing one- or two-level TLIF for degenerative pathologies were identified and data were extracted on demographics, baseline lumbopelvic radiographic parameters, and TLIF details. The primary outcome of interest was the degree to which postoperative SL approximated the listed cage lordosis (Δtarget). Change in SL was a secondary outcome. Linear mixed-effects modeling was used to identify significant predictors of the percentage of ideal lordosis achieved. RESULTS A total of 239 treated levels were included (median patient age 66.6 years; 56.9% female); 151 levels were part of single-level TLIF constructs. The median segmental corrections were a 2.8° increase in SL and 2.8 mm in disc height. The median difference between listed cage lordosis and postoperative SL (Δtarget) was 0.5°. However, only 56.1% of levels achieved at least the listed cage lordosis. Linear mixed-effects modeling found that independent predictors of Δtarget were lower implant lordosis (estimate −1.01° [95% CI −1.15° to −0.87°] per degree, p < 0.001), greater preoperative SL (estimate 0.38° [95% CI 0.28°–0.48°] per degree, p < 0.001), greater preoperative PI (estimate 0.06° [95% CI 0.02°–0.11°] per degree, p = 0.007), and closer approximation of the anterior apophyseal ring of the caudal vertebrae (estimate −0.27° [95% CI −0.39° to −0.15°] per mm, p < 0.001). Similarly, independent predictors of postoperative SL were larger implant lordosis (estimate 0.16° [95% CI 0.05°–0.27°] per degree, p = 0.004), lower preoperative SL (estimate −0.70° [95% CI −0.79° to −0.62°] per degree, p < 0.001), greater preoperative PI (estimate 0.08° [95% CI 0.04°–0.12°] per degree, p < 0.001), and closer approximation of the anterior apophyseal ring of the cranial vertebrae (estimate −0.15° [95% CI −0.28° to −0.03°] per mm, p = 0.014). CONCLUSIONS The present results suggest that while lordosing, only 56% TLIF operations obtain the listed interbody lordosis ("target" lordosis). Anterior placement within the disc space is the only modifiable intraoperative technical factor for maximizing lordosis for a given interbody, highlighting the importance of effective disc space exenteration.

BACKGROUND AND OBJECTIVES: The Patient-Generated Subjective Global Assessment (PG-SGA) is a standardized tool for assessing malnutrition in patients with cancer. The primary aim of this study was to assess the impact of preoperative nutritional status as measured by PG-SGA on survival in patients requiring surgical intervention and/or radiotherapy for spinal metastases. METHODS: Patients with spinal metastases who underwent surgery and/or radiation therapy for symptomatic spinal metastases were enrolled in the AO Spine Metastatic Tumor Research and Outcomes Network, a prospective international multicenter research registry, between September 2017 and August 2022. Using the PG-SGA, nutritional status was classified into 3 categories: A, well nourished; B, moderately malnourished; and C, severely malnourished. RESULTS: A total of 589 patients met the inclusion criteria; 362 were classified as well nourished (61%), 159 were moderately malnourished (27%), and 68 were severely malnourished (12%). The median survival was 491 days, 328 days, and 117 days for well-nourished, moderately malnourished, and severely malnourished patients, respectively. In the multivariate analyses, severe malnourishment (HR 2.5 95% CI 1.4-4.3, P < .01) and an ECOG performance status of 3 or 4 (HR 2.7 95% CI 1.2-6.0) remained associated with significantly worse survival. CONCLUSION: Malnutrition as measured by the PG-SGA demonstrated to be significantly and independently associated with postoperative survival. The PG-SGA is a simple and useful tool to identify spinal metastases patients at risk of early postoperative mortality, and inclusion in the preoperative evaluation of these patients should be considered.

Study Design This study is part of the AO Spine Metastatic Tumor Research and Outcomes Network [MTRON], an international multicenter prospective observational registry including patients with spinal metastases. Objectives This study aims to elucidate the incidence of surgical complications, their risk factors and consequent effects on survival outcomes, hospital length of stay, and overall health-related quality of life (HRQOL) parameters in a large cohort of patients affected by spinal metastases who were surgically treated. Methods Available data from February 2017 to July 2023 were analyzed. The primary outcome of this study was the evaluation of the incidence of intraoperative and postoperative adverse events (AEs). The secondary outcomes included the assessment of risk factors for surgery-related AEs and the impact of AEs on survival, length of hospital stay and quality of life. Results Among the 1267 patients analyzed, 6.9% experienced intraoperative AEs and 19.3% experienced at least 1 postoperative AE. Several factors resulted to be associated to the occurrence of postoperative AEs: age, smoking habit, poor Eastern Cooperative Oncology Group (ECOG) Performance status, previous radiation therapy at the index target, duration of surgery, number of instrumented levels, simultaneous anterior and posterior approach, presence of metastases at other sites, multiple spinal metastases. Postoperative AEs were associated with reduced survival rates, increased hospital length of stay and poorer HRQOL outcomes, particularly in domains such as neurological function and mental health. In general, surgery substantially improves HRQOL across multiple domains, with these benefits persisting over time despite the occurrence of AEs. However, patients with preoperative risk factors, including comorbidities, smoking, neurological impairment, and prior radiation therapy, experienced less improvement. Conclusions The negative impact of AEs on overall survival and HRQOL could be associated with the presence of some preoperative parameters of frailty that are detected as risk factors for AEs occurrence. This finding emphasizes the need for personalized preoperative assessments and optimized perioperative care strategies.

OBJECTIVE Spinal stereotactic radiosurgery (SSRS) is an established treatment modality for spinal metastatic disease. A common complication of SSRS is postradiation pathologic fracture. The authors evaluated the risk of pathologic fracture in sacral SSRS. METHODS All patients receiving SSRS in 1 to 5 fractions to 1 or more sacral levels between 2011 and 2020 at participating institutions were included. Demographic, histological, anatomical, and outcome data were obtained from electronic medical records. Data were analyzed using SPSS version 28. RESULTS Of 67 total patients, 50 (74.6%) were men and 17 (25.4%) were women. The most common tumor histologies were prostate adenocarcinoma (n = 16 [23.9%]) and renal cell carcinoma (n = 12 [17.9%]). Median (range) age at treatment was 63 (8–87) years. The mean ± SD (range) number of levels treated was 1.5 ± 0.7 (1–4) levels. Mean ± SD (range) bone density at S1 was 208.0 ± 74.4 (−3.0 to 443.3) Hounsfield units (HUs). Median (range) follow-up was 16.6 (1.5–132) months, median ± SD (range) overall survival was 24 ± 21.0 (1.7–83.3) months, and the 1-year local control rate was 83.6%. Fourteen patients (20.9%) experienced fracture within the radiation field. There was no association between fracture and patient sex (p = 0.32), age (p = 0.40), S1 HU (p = 0.28), tumor location according to Denis classification (p = 0.87), presence of pain (p = 0.66), single versus multifraction radiation (p = 0.44), or number of levels treated (p = 0.52). Patients experiencing in-field progression were more likely to experience fracture (61.5% vs 10.2%, p < 0.001), and patients experiencing fracture had a higher average Spine Instability Neoplastic Score than patients without fracture (5.7 vs 4.3, p = 0.049). Only local control remained as a factor associated with sacral fracture in the multivariate analysis. Of the patients experiencing fracture, 10 (71.4%) were symptomatic and 3 of those (30.0%) underwent post-SSRS surgical intervention. CONCLUSIONS Pathologic fracture may occur after sacral SSRS in a significant number of patients and is significantly associated with failure of local control.

OBJECTIVE The purpose of this study was to identify risk factors for mechanical complications following complex spinal reconstruction for spondylectomy of primary spinal column tumors. METHODS A retrospective chart review identified patients treated with spondylectomy for primary spinal column tumors in the thoracic or lumbar spine followed by posterior instrumentation and anterior column reconstruction. Variables collected included basic demographics, smoking status, chronic steroid use, frailty (Charlson Comorbidity Index), extent of resection, Weinstein-Boriani-Biagini classification, tumor volume, Spine Instability Neoplastic Score, anterior column reconstruction and fixation techniques, rod characteristics, Hounsfield units (HUs), and neoadjuvant/adjuvant chemoradiation. RESULTS Twenty-five patients were included (14 men, 11 women) with an average (± SD) age of 45 ± 18 years, BMI of 28 ± 5.7, and follow-up of 6.0 ± 6.2 years. Primary spinal column tumor pathology included chordoma (40%), chondrosarcoma (16%), giant cell tumor (16%), osteosarcoma (16%), osteoblastoma (8%), and aneurysmal bone cyst (4%). Six patients (24%) experienced mechanical complications, including rod fractures (n = 5) and distal junctional failure (n = 1). Of the 6 patients with mechanical complications, 4 (67%) underwent reoperation. The length of follow-up was the only statistically significant risk factor for patients with mechanical complications (average 11 years) compared to those without complications (average 4.4 years, p = 0.047). Average HUs were 144 for mechanical complication patients versus 180 for those without (p = 0.08). Anterior column reconstruction materials included a titanium cage (13 patients, 3 failures), structural allograft (6 patients, 2 failures), vascularized fibular strut autograft (6 patients, no failures), nonvascularized structural autograft (5 patients, 1 failure), vascularized rib autograft (5 patients, 2 failures), and a polyetheretherketone cage (2 patients, no failures). The vascularized fibular strut autograft had a 0% mechanical failure rate, but this did not reach statistical significance (p = 0.28). Twelve patients (48%) had anterior fixation placed, with a 17% rate of mechanical complications (p = 0.65). Five patients (20%) had > 2-rod constructs, with a 20% mechanical complication rate (p = 0.99). CONCLUSIONS Reconstruction following primary spinal column tumor resection is a significant challenge, as evident by a high rate of mechanical complications and instrumentation failure. Future studies are needed with larger sample sizes to identify techniques that may mitigate the risk of failure.

OBJECTIVE Transforaminal lumbar interbody fusion (TLIF) offers both indirect decompression and segmental correction through restoration of disc height. However, stresses exerted on the vertebral endplates by the interbody device can result in implant subsidence and loss of correction. The present time-to-event analysis aimed to identify predictors of interbody subsidence. METHODS Patients who underwent 1- or 2-level TLIF were identified. Data on demographics, surgical details, preoperative bone quality using CT-based Hounsfield units (HU), and pre- and postoperative lumbopelvic parameters were collected. Univariable analyses were conducted to identify predictors of subsidence (≥ 2-mm intrusion of interbody into cranial or caudal vertebrae) and significant subsidence (≥ 4-mm intrusion). Multivariable Cox regression was performed to identify independent predictors of subsidence, expressed as hazard ratios with 95% confidence intervals. RESULTS A total of 198 patients treated at 241 levels were included (median age 66.6 years, IQR 59.5, 73.7 years; 56.6% were women). In 92 levels (38.2%) there was some subsidence and in 25 (10.4%) there was significant subsidence. Implanted levels demonstrating subsidence (≥ 2 mm) were associated with lower HU in cranial and caudal vertebrae; had interbodies positioned farther from the anterior apophyseal ring; were implanted with taller, more lordotic interbodies; and underwent greater disc height restoration. Those showing significant subsidence (≥ 4 mm) were similarly associated with lower HU in the cranial and caudal vertebrae; had interbodies positioned farther from the anterior apophyseal ring of the caudal vertebrae; and underwent greater disc height restoration. Multivariable Cox regression showed that time to subsidence was predicted by greater implant height (HR 1.20/mm, 95% CI 1.05–1.38; p = 0.009), greater postoperative disc height (HR 1.21/mm, 95% CI 1.09–1.34; p < 0.001), and greater disc height restoration (HR 1.11/mm, 95% CI 1.04–1.19; p = 0.002). The time-to-subsidence analysis for significant (≥ 4 mm) subsidence showed that it was predicted by lower HU in the cranial vertebrae (HR 0.98/unit, 95% CI 0.97–0.99; p = 0.001); increasing number of levels instrumented (HR 1.26, 95% CI 1.04–1.52; p = 0.016); and greater disc height restoration (HR 1.33/mm, 95% CI 1.18–1.51; p < 0.001). CONCLUSIONS This time-to-event analysis suggests that interbody subsidence following TLIF is best predicted by implantation of a taller interbody and aggressive disc height restoration. Significant subsidence is similarly predicted by aggressive disc height restoration along with poor baseline bone quality. The results suggest the need to balance aggressive correction at the time of surgery against the increased risk of subsequent interbody subsidence.

Introduction: Bone health optimization is a key component of the preoperative management of spine surgery patients, as poor bone quality increases the odds of mechanical complications. The present study aimed to achieve the following: (1) compare the relative efficacy of current osteoporosis medications in improving bone quality; (2) identify factors influencing treatment response in preoperative spine surgery patients. Methods: Patients treated at a single, multisite institution who received osteoporosis treatment were identified. Data were gathered on pre- and post-treatment lumbar spine Hounsfield Unit (HU) measurements, patient demographics, frailty scores (modified Frailty Index/mFI, risk analysis index/RAI), and pharmacologic treatment details. The primary outcome was a ≥7 point improvement in lumbar HU, and baseline and logistic regression models were utilized to identify factors associated with this improvement. Medications were grouped as anabolic (teriparatide, romosozumab) and antiresorptive (denosumab, alendronate) therapies. Results: A total of 267 patients were included (median age: 74 years; IQR [66–81]; 67.3% female), with 127 (47.6%) improving by ≥7 HU. The treatment agents used were alendronate (95), denosumab (113), romosozumab (31), and teriparatide (28). Univariable comparisons revealed significant differences across medication groups in age (p < 0.001), sex (p < 0.001), mFI (p < 0.001), RAI (p = 0.004), BMI (p < 0.001), pre-treatment HU (p = 0.022), and treatment duration (p < 0.001). The highest HU improvement rates (ΔHU ≥ 7) were observed in patients receiving the anabolic medications romosozumab (67.7%) and teriparatide (60.7%). Univariable logistic regression identified male sex (OR 0.54, p = 0.019), higher pre-treatment HU (OR 0.99, p = 0.006), and longer treatment duration (OR 0.97, p = 0.003) as factors associated with lower odds of HU improvement. Only romosozumab was associated with significantly higher odds of HU improvement relative to alendronate (OR 3.02, p = 0.012). In our multivariable analysis, male sex (OR 0.53, p = 0.028) and higher pre-treatment HU (OR 0.99, p = 0.002) remained significant predictors of HU improvement. However, medication type was not significant in the multivariable analysis. Conclusions: Our study highlights that male sex and higher pre-treatment HU were independently associated with lower odds of HU improvement, while medication type was not a significant predictor. Additionally, anabolic agents offered superior improvement relative to antiresorptive therapies.

OBJECTIVE Surgery is typically indicated for mechanical pain in metastatic spine disease or severe neurological compromise, but how radicular pain responds to oncological treatment is not well described. The primary aim of this study was to describe how radicular pain responds to oncological treatment, while secondary aims included pain outcomes between patients with mechanical and tumoral pain and motor improvement in patients with weakness due to nerve root compression. METHODS Patients treated with surgery and/or radiotherapy for spinal metastases were identified from an international multicenter prospective cohort. The primary outcome was the numeric rating scale (NRS) score for pain at 3 months posttreatment. Motor recovery from radicular compression in patients with myotomic weakness and low-grade epidural compression was also analyzed. RESULTS Of 284 patients, 129 (45%) had radicular pain ± axial pain and 155 (55%) had axial pain alone. The two groups did not significantly differ in age, comorbidities, tumor characteristics, or treatment. Two hundred two patients (71%) underwent surgery ± radiotherapy, whereas 82 (29%) had radiotherapy alone. The NRS score of patients with radicular pain improved from 6.7 to 3.4 at 3 months, a statistically significantly higher magnitude than in patients with isolated axial pain (p = 0.021). The NRS score at 3 months was similar for both groups (p = 0.876). Patients with radicular pain experienced a larger improvement with surgery compared with radiotherapy alone (p = 0.007) but had higher pretreatment pain (mean NRS score 7.0 vs 5.6, p = 0.013). Twenty-three patients identified with radicular/myotomic weakness (mean American Spinal Injury Association score 96.3 ± 3.2) at baseline improved 2.1 ± 3.8 points at 3 months. CONCLUSIONS The magnitude of pain improvement for patients with radicular pain following surgery and radiotherapy for metastatic spine disease is higher than for patients with axial pain alone. Surgery is associated with a larger improvement in radicular pain than radiotherapy alone. These results will allow clinicians to tailor treatment options for patients with metastatic spine disease.