Fusion rate of Escherichia coli-derived recombinant human bone morphogenetic protein-2 compared with local bone autograft in posterior lumbar interbody fusion for degenerative lumbar disorders.

BACKGROUND CONTEXT: The use of recombinant human bone morphogenetic proteins-2 (rhBMP-2) for spinal fusion has been reported to be effective. However, most studies have focused on posterolateral and anterior lumbar interbody fusion, and few have investigated posterior lumbar interbody fusion (PLIF). PURPOSE: This study aimed to determine the effectiveness and safety of the delivery of Escherichia coli-derived rhBMP-2 (E.BMP-2) with hydroxyapatite (HA) and ß-tricalcium phosphate (ß-TCP) poloxamer hydrogel composite carriers for PLIF. STUDY DESIGN: A retrospective study. PATIENT SAMPLE: Patients who underwent 1 to 3 levels of PLIF for lumbar degenerative disc disorders between 2015 and 2020 with a follow-up of ≥1 year were enrolled. In total, 254 patients (357 levels) were included in the analysis. The evaluation was performed at each segment level. In the E.BMP-2 group, 160 patients (221 levels) received autologous local bone with E.BMP-2 (maximum 0.5 mg/level), and in the control group, 94 patients (136 levels) received only local bone graft. OUTCOME MEASURES: The primary outcome of this study was to compare the X-ray and CT fusion rates between the two groups. Secondary outcomes included analysis of the patients' clinical outcomes and postoperative complications on CT scans. METHODS: Clinical evaluations were performed using a visual analog scale for back pain, the Oswestry Disability Index for disability, and physical and mental component summaries of the Short Form 36-Item Form Health Survey to assess functional effects and quality of life. The fusion was evaluated using radiography and CT. On radiography, solid fusion was defined when the difference between extension and flexion was less than 5°. On CT, solid fusion was defined when the upper and lower vertebral bodies were connected by the trabecular bone (bone bridge formation). In addition, complications such as osteolysis, cage subsidence, and screw loosening were investigated using CT. RESULTS: All clinical results for low back pain, disability, and quality of life in both groups were excellent and showed statistically significant improvements compared with baseline (p<.0001). According to the X-ray evaluations, fusion was achieved in 92.31% (204/221) of the patients in the E.BMP-2 group and 82.35% (112/136) of the patients in the control group (p=.0041). According to the CT evaluations, the fusion rates were 93.21% (206/221) and 88.24% (120/136) in the E.BMP-2 and control groups (p=.1048), respectively. Except for screw loosening, which had a significantly higher incidence in the control group (p=.0014), the rates of most postoperative complications were not significantly different between the groups. CONCLUSIONS: This study demonstrated that the adjunctive use of a low dose of E.BMP-2 with HA and ß-TCP hydrogel can effectively promote bone fusion, making it a promising option for patients with limited autograft availability or compromised bone quality in PLIF.

What Affects Segmental Lordosis of the Surgical Site after Minimally Invasive Transforaminal Lumbar Interbody Fusion?

PURPOSE: This study was undertaken to identify factors that affect segmental lordosis (SL) after minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF) by comparing patients whose postoperative SL increased with those whose decreased. MATERIALS AND METHODS: Fifty-five patients underwent MIS-TLIF at our institute from January 2018 to September 2019. Demographic, pre- and postoperative radiologic, and cage-related factors were included. Statistical analyses were designed to compare patients whose SL increased with decreased after surgery. RESULTS: After surgery, SL increased in 34 patients (group I) and decreased in 21 patients (group D). The index level, disc lordosis, SL, lumbar lordosis, proximal lordosis (PL), and Y-axis position of the cage (Yc) differed significantly between groups I and D. The cage in group I was more anterior than that in group D (Yc: 55.84% vs. 51.24%). Multivariate analysis showed that SL decreased more significantly after MIS-TLIF when the index level was L3/4 rather than L4/5 [odds ratio (OR): 0.46, p=0.019], as preoperative SL (OR: 0.82, p=0.037) or PL (OR: 0.68, p=0.028) increased, and as the cage became more posterior (OR: 1.10, p=0.032). CONCLUSION: Changes in SL after MIS-TLIF appear to be associated with preoperative SL and PL, index level, and Yc. An index level at L4/5 instead of L3/4, smaller preoperative SL or PL, and an anterior position of the cage are likely to result in increased SL after MIS-TLIF.

Could Machine Learning Better Predict Postoperative C5 Palsy of Cervical Ossification of the Posterior Longitudinal Ligament?

STUDY DESIGN: This was a retrospective cohort study. OBJECTIVE: The objective of this study was to investigate whether machine learning (ML) can perform better than a conventional logistic regression in predicting postoperative C5 palsy of cervical ossification of the posterior longitudinal ligament (OPLL) patients. SUMMARY OF BACKGROUND DATA: C5 palsy is one of the most common postoperative complications after surgical treatment of OPLL, with an incidence rate of 1.4%-18.4%. ML has recently been used to predict the outcomes of neurosurgery. To our knowledge there has not been a study to predict postoperative C5 palsy of cervical OPLL patient with ML. METHODS: Four sampling methods were used for data balancing. Six ML algorithms and conventional logistic regression were used for model development. A total of 35 ML prediction model and 5 conventional logistic prediction models were generated. The performances of each model were compared with the area under the curve (AUC). Patients who underwent surgery for cervical OPLL at our institute from January 1998 to January 2012 were reviewed. Twenty-five variables of each patient were used to make a prediction model. RESULTS: In total, 901 patients were included [651 male and 250 female, median age: 55 (49-63), mean±SD: 55.9±9.802]. Twenty-six (2.8%) patients developed postoperative C5 palsy. Age (P=0.043), surgical method (P=0.0112), involvement of OPLL at C1-3 (P=0.0359), and postoperative shoulder pain (P≤0.001) were significantly associated with C5 palsy. Among all ML models, a model using an adaptive reinforcement learning algorithm and downsampling showed the largest AUC (0.88; 95% confidence interval: 0.79-0.96), better than that of logistic regression (0.69; 95% confidence interval: 0.43-0.94). CONCLUSIONS: The ML algorithm seems to be superior to logistic regression for predicting postoperative C5 palsy of OPLL patient after surgery with respect to AUC. Age, surgical method, and involvement of OPLL at C1-C3 were significantly associated with C5 palsy. This study demonstrates that shoulder pain immediately after surgery is closely associated with postoperative C5 palsy of OPLL patient.

Immediate postoperative measurement of thyroid-stimulating hormone as an early predictor of remission in thyroid-stimulating hormone-secreting pituitary adenomas.

OBJECTIVE: Thyroid-stimulating hormone (TSH)-secreting pituitary adenoma (TSHoma) is a rare type of pituitary adenoma; thus, little is known about TSHomas. The purpose of this study was to analyze clinical characteristics and therapeutic outcomes of TSHomas based on a single-center experience. The authors also searched for reliable preoperative and early postoperative factors that could predict long-term endocrinological remission. METHODS: The clinical, radiological, and pathological characteristics and surgical and endocrinological outcomes of 31 consecutive cases of TSHomas that were surgically treated between 2005 and 2017 were reviewed retrospectively. Preoperative factors were evaluated for their ability to predict long-term remission by comparing remission and nonremission groups. TSH and free thyroxine levels were measured at 2, 6, 12, 18, and 24 hours after surgery to determine whether they could predict long-term remission. RESULTS: Gross-total removal of tumor was achieved in 28 patients (90.3%), and 26 patients (83.9%) achieved endocrinological remission by surgery alone based on long-term endocrinological follow-up (median 50 months, range 32-81 months). The majority of the tumors were solid (21/31, 67.7%), and en bloc resection was possible in 16 patients (51.6%). Larger tumor size and tumor invasion into cavernous sinus and sphenoid sinus were strong predictors of lower rates of endocrinological remission. Immediate postoperative TSH level at 12 hours after surgery was the strongest predictor, with a 0.62 µIU/mL cutoff. Postoperative complications included CSF rhinorrhea in one patient and epistaxis in another patient, who underwent additional surgical treatment for the complications. CONCLUSIONS: Tumor size and extent are major prognostic factors for both extent of resection and endocrinological remission. The consistency of TSHomas was more likely to be solid, which makes extracapsular dissection more feasible. Long-term remission of TSHomas could be predicted even during the early postoperative period.