Study Design Retrospective cohort study Objectives This study aimed to report the incidence and potential risk factors of polyetheretherketone (PEEK) cage subsidence following oblique lateral interbody fusion (OLIF) for lumbar degenerative diseases. We proposed also an algorithm to minimize subsidence following OLIF surgery. Methods The study included a retrospective cohort of 107 consecutive patients (48 men and 59 women; mean age, 67.4 years) who had received either single- or multi-level OLIF between 2012 and 2019. Patients were classified into subsidence and non-subsidence groups. PEEK cage subsidence was defined as any violation of either endplate from the computed tomography scan in both sagittal and coronal views. Preoperative variables such as age, sex, body mass index, bone mineral density (BMD) measured by preoperative dual-energy X-ray absorptiometry, smoking status, corticosteroid use, diagnosis, operative level, multifidus muscle cross-sectional area, and multifidus muscle fatty degeneration were collected. Age-related variables (height and length) were also documented. Univariate and multivariate logistic regression analyses were used to analyze the risk factors of subsidence. Results Of the 107 patients (137 levels), 50 (46.7%) met the subsidence criteria. Higher PEEK cage height had the strongest association with subsidence (OR = 9.59, P < .001). Other factors significantly associated with cage subsistence included age >60 years (OR = 3.15, P = .018), BMD <−2.5 (OR = 2.78, P = .006), and severe multifidus muscle fatty degeneration (OR = 1.97, P = .023). Conclusions Risk factors for subsidence in OLIF were age >60 years, BMD < −2.5, higher cage height, and severe multifidus muscle fatty degeneration. Patients who had subsidence had worse early (3 months) postoperative back and leg pain.

To compare clinical and radiographic outcomes among minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF), extreme lateral lumbar interbody fusion (XLIF), and oblique lateral lumbar interbody fusion (OLIF) techniques. Overview of Literature: To date, there are many reports comparing outcomes between MIS-TLIF and XLIF, MIS-TLIF and OLIF, or XLIF and OLIF procedures. However, there are no previous studies comparing clinical and radiographic outcomes among all these three techniques. Methods: Data from patients who underwent minimally invasive (MI) fusion surgery for lumbar degenerative diseases at L4-L5 level was analyzed. Thirty patients each from MIS-TLIF, XLIF, and OLIF groups were recruited for propensity score matching. Visual Analog Scale (VAS) of the back and legs and Oswestry Disability Index (ODI) were evaluated preoperatively and at 1, 3, and 6 months and 1 year postoperatively. Radiographic outcomes were also compared. The fusion rate was evaluated at 1 year after surgeries. Results: The clinical outcomes were significantly improved in all groups. The disk height was significantly restored in all groups postoperatively, which was significantly more improved in XLIF and OLIF than MIS-TLIF group (p<0.001). The axial canal area was significantly increased more in MIS-TLIF versus XLIF and OLIF (p<0.001). The correction of lumbar lordotic angle and segmental sagittal angle were similar among these techniques. OLIF and XLIF groups showed less blood loss and shorter hospital stays than MIS-TLIF group (p<0.001). There was no significant difference in fusion rate among all groups. Conclusions: MIS-TLIF, XLIF, and OLIF facilitated safe and effective MI procedures for treating lumbar degenerative diseases. XLIF and OLIF can achieve clinical outcomes equivalent to MIS-TLIF by indirect decompression. XLIF and OLIF showed less blood loss, shorter hospital stays, and better disk and foraminal height restorations. In single-level L4-5, the restoration of sagittal alignment was similar between these three techniques.

BACKGROUND:Surgical resection of the ventrally located tumor in the cervical spinal region is technically challenging and usually requires a traditional extensive approach. To reduce collateral injury and preserve cervical stability, the anterior transcorporeal approach under navigated guidance is an alternative minimally invasive technique.OBJECTIVE:To describe a minimally invasive transcorporeal approach for cervical intradural extramedullary tumor resection and spinal cord decompression. Previous literature regarding available treatment options was reviewed.METHODS:A patient with known intracranial malignant melanoma presented with severe myelopathy from metastatic melanoma compressing the cervical cord. The anterior transcorporeal approach for total tumor resection and spinal cord decompression under a microscope was planned. Under spinal navigation, small bone tunneling was performed to expose and remove the tumor without compromising cervical stability.RESULTS:The melanoma resection was successfully performed without complications. Myelopathic symptoms were significantly improved with the absence of instability or local recurrence at the long-term follow-up.CONCLUSION:We present the anterior transcorporeal approach that can be used to resect the tumor in the ventral cervical region and effectively decompress the cervical cord without complications. Moreover, this approach is the minimally invasive surgical technique that preserves spinal stability, minimizes bleeding, and shortens the hospital stay.

Background: Extreme lateral interbody fusion (XLIF) is a minimally invasive surgery that accesses the lumbar spine through the psoas muscle. This study aimed to evaluate the correlation between the psoas major muscle volume and anterior thigh symptoms after XLIF. Methods: Eighty-one patients (mean age 63 years) with degenerative spine diseases underwent XLIF (total = 94 levels). Thirty-eight patients were female (46.9%), and 24 patients (29.6%) had a history of lumbar surgery. Supplemental pedicle screws were used in 48 patients, and lateral plates were used in 28 patients. Neuromonitoring devices were used in all cases. The patients were classified into two groups (presence of thigh symptoms and no thigh symptoms after the surgery). The psoas major volumes were measured and calculated by CT (computed tomography) scan and compared between the two patient groups. Results: In the first 24 h after surgery, 32 patients (39.5%) had thigh symptoms (20 reported pain, 9 reported numbness, and 18 reported weakness). At one year postoperatively, only 3 of 32 patients (9.4%) had persistent symptoms. Conclusions: As a final observation, no statistically significant difference in the mean psoas major volume was found between the group of patients with new postoperative anterior thigh symptoms and those with no thigh symptoms. Preoperative psoas major muscle volume seems not to correlate with postoperative anterior thigh symptoms after XLIF.

Purpose: No consensus criteria have been established regarding ideal candidates for indirect decompression with lateral lumbar interbody fusion (LLIF), and contributing factors of indirect decompression failure were rarely reported. We aim to investigate the success rate of indirect decompression by LLIF with proposed selection criteria and identify risk factors associated with indirect decompression failure, defined as persistent pain requiring revision with direct decompression. Methods: Data from 191 patients undergoing LLIF were retrospectively reviewed. All the following criteria must be fulfilled: 1) dynamic clinical symptoms (pain relief in supine position), 2) presence of reducible disc height (recovered disc height in supine position), 3) no profound weakness and 4) no static stenosis. The success rate of indirect decompression with LLIF and results after at least 1-year of follow-up were collected. Preoperative, procedure-related, and postoperative factors were assessed for their relationship with failure. Results: Of 191 patients,13 patients (6.8%) required additional direct decompression due to persistent pain, giving a criteria success rate of 93.2%. Factors associated with indirect decompression failure included low bone mineral density (BMD) (T-score < 2.1), low reducible disc height (<13%), low postoperative disc height (<10 mm), high-grade cage subsidence, and use of plate fixation. Conclusion: We proposed patient selection criteria for indirect decompression with LLIF which had a satisfactory success rate and identified factors associated with the need for additional direct decompression. Our proposed criteria may assist selection of patients likely to achieve good results following indirect decompression with LLIF, and optimize selection based on risk factors of failure.

This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.

Background: Osteoid osteoma (OO) is a common benign bone tumor; however, approximately 25% of cases have spine involvement. It is often treated by image-guided radiofrequency ablation to break down the nidus. Few reports have described full endoscopic resection of the lesion, but none have described postoperative remodeling of the lumbar facet joint after surgical resection of an OO. The study aimed to describe a rare case of remodeling of the lumbar facet joint and then delineate the least invasive surgical technique of endoscopic resection of an OO.Methods: A 26-year-old man presented with severe left buttock pain and sciatica that worsened at night and was relieved by ibuprofen. Magnetic resonance imaging indicated a left inferior facet of an L3 mass-like lesion. A thin-section computed tomography image revealed a nidus, which was compatible with an OO. Full endoscopic resection was performed to completely remove the nidus of the OO.Results: At the 2-year follow-up, the patient was symptom-free and computed tomography images indicated new bone formation.Conclusions: The present case and literature review demonstrate that endoscopic resection is safe and effective for managing a posterior element of lumbar OO. Furthermore, this technique allows complete removal of the nidus with minimal damage to surrounding structures and leads to remodeling of the resection site.Clinical Relevance: Patients with OO involving the posterior element of the spine can present with buttock and radicular pain, mimicking lumbar disc herniation. OO can be successfully removed by the full endoscopic method and remodeling of the resected site can be anticipated.Level of Evidence: 4.

Study Design Meta-analysis and systematic review. Objective This study aims to investigate and compare patient-reported outcomes, perioperative data, and complications between 2 common endoscopic approaches for lumbar disc herniation: transforaminal and interlaminar endoscopic lumbar discectomy, by published high-quality evidence. Methods Electronic databases were searched for reported outcomes following TELD and IELD. Oswestry Disability Index (ODI), visual analog scale of back (VASB) and leg pain (VASL), and MacNab criteria were evaluated. Operative time, hospital stays, blood loss, radiation exposure, and complications were investigated. Odds ratio (OR) and mean differences (MD) with 95% confidence intervals (CI) were calculated using random and fixed-effect models. Results Total of 1948 patients from 18 studies were included, consisting of 1006 patients (51.6%) in TELD group and 942 (48.4%) patients in IELD group. TELD had better improvement of postoperative ODI (MD = 1.26; 95% CI: .07-2.16; P = .04), postoperative VASB (MD = −.23; 95% CI: −.40 to −.05; P = .01) and last follow-up VASB (MD = −.25; 95% CI: −.41 to −.09; P = .002), but with longer operative time (MD = 10.1 min; 95% CI: 1.925-18.77; P < .00001) and more fluoroscopic time (SMD = 4.12; 95% CI: 3.22-5.03; P < .00001), especially in L5-S1 operation. Bed rest time was significantly longer following IELD, with no difference in VASL, hospital stays, or complication. Conclusion We found comparable clinical outcomes in terms of ODI, VAS, patient satisfaction, hospital stays, and complication between both techniques. TELD required more radiation exposure and longer operative time at L5-S1 level than IELD. Our study provided results to help consider appropriate approaches for selected patients and informed consent of benefits from each approach.