Dose-escalated radiotherapy with simultaneous integrated boost for bone metastases in selected patients with assumed favourable prognosis.

BACKGROUND: Stereotactic body radiotherapy (SBRT) concepts for dose escalation are increasingly used for bone metastases in patients with oligometastatic or oligoprogressive disease. For metastases that are not suitable for SBRT-regimens, a treatment with 30/40 Gy with simultaneous integrated boost (SIB) in 10 fractions represents a possible regimen. The aim of this study was to investigate the feasibility of this concept and the acute and subacute toxicities. PATIENTS AND METHODS: Clinical records for dose-escalated radiotherapy of all consecutive patients treated with this regimen were evaluated retrospectively (24 patients with 28 target volumes for oncologic outcomes and 25 patients with 29 target volumes for treatment feasibility and dose parameters analysis). Analysis of radiotherapy plans included size of target volumes and dosimetric parameter for target volumes and organs at risk (OAR). Acute and subacute toxicities were evaluated according to Common Terminology Criteria for Adverse Events (CTCAE) V4.0. RESULTS: The most common localization was the spine (71.4%). The most common histology was prostate cancer (45.8%). Oligometastatic or oligoprogressive disease was the indication for dose-escalated radiotherapy in 19/24 patients (79.2%). Treatment was feasible with all patients completing radiotherapy. Acute toxicity grade 1 was documented in 36.0% of the patients. During follow up, one patient underwent surgery due to bone instability. The 1-year local control and patient-related progression-free survival (PFS) were 90.0 ± 6.7% and 33.3 ± 11.6%, respectively. CONCLUSIONS: Dose-escalated hypofractionated radiotherapy with simultaneous integrated boost for bone metastases resulted in good local control with limited acute toxicities. Only one patient required surgical intervention. The regimen represents an alternative to SBRT in selected patients.

Influence of Cage Design on Radiological and Clinical Outcomes in Dorsal Lumbar Spinal Fusions: A Comparison of Lordotic and Non-Lordotic Cages.

OBJECTIVES: To evaluate the comparison between lordotic and non-lordotic transforaminal lumbar interbody fusion (TLIF) cages in degenerative lumbar spine surgery and analyze radiological as well as clinical outcome parameters in long-term follow up. METHODS: In a retrospective study design, we compared 37 patients with non-lordotic cage (NL-group) and 40 with a 5° lordotic cage (L-group) implanted mono- or bi-segmental in TLIF-technique from 2013 to 2016 and analyzed radiological parameters of pre- and postoperative (Lumbar lordosis (LL), segmental lordosis (SL), and pelvic tilt (PT), as well as clinical parameters in a follow-up physical examination using the Oswestry disability index (ODI), Roland-Morris Score (RMS), and visual analog scale (VAS). RESULTS: Surgery was mainly performed in lower lumbar spine with a peak in L4/5 (mono-segmental) and L4 to S1 (bi-segmental), long-term follow-up was on average 4 years postoperative. According to the literature, we found significantly better results in radiological outcome in the L-group compared to the NL-group: LL increased 6° in L-group (51° preoperative to 57° postoperative) and decreased 1° in NL-group (50° to 49° (P < 0.001). Regarding SL, we found an increase of 5° in L-group (13° to 18°) and no difference in NL-group (15°)(P < 0.001). In PT, we found a clear benefit with a decrease of 2° in L-group (21° to 19°) and no difference in NL-group (P = 0.008). In direct group comparison, ODI in NL-group was 23% vs 28% in L-group (P = 0.25), RMS in NL-group was 8 points vs 9 points in L-group (P = 0.48), and VAS was in NL-group 2.7 vs 3.2 in L-group (P = 0.27) without significant differences. However, the clinical outcome in multivariate analysis indicated a significant multivariate influence across ODI and RMS of BMI (Wilks λ = 0.57, F [4, 44] = 3.61, P = 0.012) and preoperative SS (Wilks λ = 0.66, F [4, 44] = 2.54, P = 0.048). Age, gender, cage type and postoperative PT had no significant influence (P > 0.05). Intraoperatively, we saw three dura injuries that could be sutured without problems and had no consequences for the patient. In the follow-up, we did not find any material-related problems, such as broken screws or cage loosening, also no pseudarthrosis. CONCLUSION: In conclusion, we think it's not cage design but other influenceable factors such as correct indication and adequate decompression that lead to surgical success and the minimal difference in the LL therefore seemed to be of subordinate importance.

Loading capacity of dynamic knee spacers: a comparison between hand-moulded and COPAL spacers.

BACKGROUND: The two-stage revision protocol represents the current gold standard for treating infected total knee replacement implants. Allowing early mobility with weight-bearing between staged procedures will enable early restoration to knee function. So, the mechanical performance of knee spacers is a key issue. Commercially available moulds are often used as they are easy to prepare and produce smoother surfaces of the articulating parts. However, they are costly, and only for single use. A cost-effective alternative is the surgeon-made hand-moulded spacers. In this study, we wanted to determine how the hand-moulded spacers will compare biomechanically with the commercially available COPAL spacers. METHODS: Seven cadaveric knees were implanted with knee spacers fabricated using COPAL knee moulds. The same surgeon implanted eight cadaveric knees with hand-moulded spacers. In the first test protocol, an axial load was applied at 200 mm/min till failure. In the second test protocol, the knees were cyclically loaded in five steps of 1000 cycles each from 30-400 N, 30-600 N, 30-800 N, 30-1000 N, 30-1200 N at 1.5 Hz. RESULTS: COPAL knee spacers demonstrated a maximum load and mean stiffness of 5202 (± 486.9) N and 1098 (± 201.5) N/mm respectively. The hand-moulded knee spacers demonstrated a mean stiffness of 4509 (± 1092.6) N and 1008.7 (± 275.4) N/mm respectively. The maximum axial displacement was 1.19 ± 0.57 mm and 0.89 ± 0.30 mm for specimens implanted with COPAL knee spacers and hand-moulded spacers respectively. The differences between COPAL and hand-moulded knee spacers were not statistically different. CONCLUSIONS: Our study demonstrated that dynamic knee spacers may be able to withstand more than the touch-down load permitted in previous studies, and this may allow more weight-bearing during ambulation. Previous studies have demonstrated that hand-moulded knee spacers have similar advantages to commercially available dynamic spacers with respect to mobility, pain, bone loss, and reinfection rate. Given that ambulation with weight-bearing up to 1200 N is permitted during rehabilitation, it may be more cost-effective to fabricate hand-moulded spacers in revision total knee arthroplasty.

Diagnosis of Lumbar Spinal Stenosis with Functional Myelography.

BACKGROUND AND STUDY AIMS: The diagnosis of a lumbar spinal stenosis demands advanced diagnostic radiologic techniques. In recent decades magnetic resonance imaging (MRI) has replaced myelography, now considered an old-fashioned technique. It was our hypothesis that functional myelography still plays an important role in selected cases. We investigated how our surgical strategy was influenced by the results of MRI, functional myelography, and postmyelography computed tomography (CT) in patients with a lumbar spinal stenosis. METHODS: The sagittal diameters of the lumbar spinal canal were measured from L1 to S1 on patients with lumbar spinal stenosis. MRI, functional myelography, and postmyelography CT were compared in each of the patients. Sensitivity and specificity were calculated in each method. We examined how the surgical strategy was influenced by the results of these different methods. RESULTS: Fifty consecutive patients (21 women and 29 men; mean age: 70 years, [range: 49-86 years]) fulfilled the inclusion criteria. Functional myelography revealed a sensitivity of 0.99, a specificity of 0.79, and a positive predictive value of 0.45. The MRI exhibited a sensitivity of 0.93, a specificity of 0.74, and a positive predictive value of 0.39. Postmyelography CT showed a sensitivity of 0.96, a specificity of 0.75, and a positive predictive value of 0.41. A functional myelography revealed more information than the MRI and resulted in a change in the surgical strategy in 11 of 50 patients (22%) in comparison with the sole results of MRI or a postmyelography CT. CONCLUSIONS: In selected cases with multilevel lumbar spinal stenosis, functional myelography revealed the highest precision in reaching a correct diagnosis. It resulted in a change in the surgical approach in every fifth patient in comparison with the MRI and proved most helpful, especially in elderly patients.

Pull out Strength of Dual Outer Diameter Pedicle Screws Compared to Uncemented and Cemented Standard Pedicle Screws: A Biomechanical in vitro Study.

OBJECTIVE: To analyze the potential of the dual outer diameter screw and systematically evaluate the pull-out force of the dual outer diameter screw compared to the uncemented and cemented standard pedicle screws with special regard to the pedicle diameter and the vertebra level. METHODS: Sixty vertebrae of five human spines (T 6 -L 5 ) were sorted into three study groups for pairwise comparison of the uncemented dual outer diameter screw, the uncemented standard screw, and the cemented standard screw, and randomized with respect to bone mineral density (BMD) and vertebra level. The vertebrae were instrumented, insertion torque was determined, and pull-out testing was performed using a material testing machine. Failure load was evaluated in pairwise comparison within each study group. The screw-to-pedicle diameter ratio was determined and the uncemented dual outer diameter and standard screws were compared for different ratios as well as vertebra levels. RESULTS: Significantly increased pull-out forces were measured for the cemented standard screw compared to the uncemented standard screw (+689 N, P < 0.001) and the dual outer diameter screw (+403 N, P < 0.001). Comparing the dual outer diameter screw to the uncemented standard screw in the total study group, a distinct but not significant increase was measured (+149 N, P = 0.114). Further analysis of these two screws, however, revealed a significant increase of pull-out force for the dual outer diameter screw in the lumbar region (+247 N, P = 0.040), as well as for a screw-to-pedicle diameter ratio between 0.6 and 1 (+ 488 N, P = 0.028). CONCLUSIONS: For clinical application, cement augmentation remains the gold standard for increasing screw stability. According to our results, the use of a dual outer diameter screw is an interesting option to increase screw stability in the lumbar region without cement augmentation. For the thoracic region, however, the screw-to-pedicle diameter should be checked and attention should be paid to screw cut out, if the dual outer diameter screw is considered.