Cervical vertebral body replacement using a modern in situ expandable and angulable corpectomy cage system: early clinical and radiological outcome.

PURPOSE: Vertebral body replacement (VBR) cages are commonly implanted to reconstruct the cervical vertebrae in cases of tumour, trauma, spondylodiscitis, and degeneration. Expandable cages have been widely used for this purpose; however, the lacking congruence at the implant-bone interface and consequent implant displacement were considered as a serious drawback of such systems. Aim of this study is to evaluate the early clinical and radiological outcome of a modern in situ not only expandable but also angulable cervical corpectomy cage system. METHODS: A total of 42 patients who underwent a single or multilevel cervical VBR procedure were included and retrospectively evaluated in this single-centre case series. The neurological status was assessed using American Spinal Injury Association (ASIA) score. Complications were categorized into surgical (including implant-associated) and general medical. Radiographic parameters included regional angulation, segmental height, and coronal alignment. RESULTS: Mean age was 59.5 ± 20.6 years. The recorded ASIA score improved postoperatively by 10 points (p  0.0001). Surgical including implant-associated complication rates were 19.05%. Radiographic evaluation showed a height gain of 11.2 mm (p < 0.0001), lordotic correction of 7° (p < 0.0001), and coronal alignment of 3° (p < 0.0001). At the last follow-up, loss of angulation correction of 1.9° (p  0.0002), subsidence of 1.92 mm (p  0.0006), and fusion rates of 68.42% were observed. CONCLUSIONS: The use of an in situ angulable and expandable cage system in cervical VBR seems to offer better results compared to conventional static or expandable cages regarding segmental height gain, lordotic correction, and clinical improvement as well as low complication and revision rates. Significant height gain in multilevel surgeries is associated with higher rates of implant-associated complications.

Feasibility of interstitial stepping-source electronic brachytherapy to locally inoperable tumors.

PURPOSE: Radiotherapy is the mainstay in the treatment of locally inoperable tumors. Interstitial electronic needle-based kilovoltage brachytherapy (EBT) could be an economic alternative to high-dose-rate (HDR) brachytherapy or permanent seed implantation (PSI). In this work, we evaluated if locally inoperable tumors treated with PSI at our institution may be suitable for EBT. MATERIAL AND METHODS: A total of 10 post-interventional computed tomography (CT) scans of patients, who received PSI and simulated stepping-source EBT applied with Intrabeam system and needle applicator were used. EBT treatment planning software with 3-dimensional image and projection of applicator were applied for designing trajectories and establishing dwell positions. Dwell position doses were summarized, and doses covering 90% of the target volume (D90) achieved with stepping-source EBT were compared to those of PSI. Additionally, conformality of dose distributions and total irradiation time were assessed using conformation number (CN) or conformal index (COIN). RESULTS: In all patients, D90 of EBT exceeded the prescribed dose or D90 of PSI on average by 4.7% or 21.3% relative to the prescribed dose, respectively. Mean number of trajectories was 5.0 for EBT and 6.9 for PSI. Average CN/COIN for EBT was 0.69, with a mean irradiation time of 27.8 minutes for standardized dose of 13 Gy. CONCLUSIONS: Stepping-source EBT allowed for a conformal treatment of inoperable interstitial tumors with similar D90. Fewer trajectories were required for EBT in majority of cases.

Long-term outcome after combined kyphoplasty and intraoperative radiotherapy (Kypho-IORT) for vertebral tumors.

INTRODUCTION: The spine represents the site which is most frequently affected by bone metastases in patients with systemic cancer. Of all local treatment options, combined kyphoplasty and intraoperative radiotherapy (Kypho-IORT) provides both, instantaneous stabilization and immediate pain relief. We here report on the long-term outcomes of the largest cohort treated with Kypho-IORT to date. METHODS: Between 2009 and 2019 a total of 104 patients underwent Kypho-IORT to vertebral tumors in the thoracic, lumbar, or sacral spine with transpedicular kyphoplasty and intraoperative irradiation with a needle-shaped electronic brachytherapy source at our center. Patients were treated either on trial, within the prospective Kypho-IORT studies (NCT01280032 and NCT02773966), or, after completion of the study, off trial but compliant with the study protocol. Follow-up and imaging with computed tomography (CT) or magnetic resonance imaging was scheduled after 3 and 6 months and then bi-annually. RESULTS: A total of 143 vertebrae (89 thoracic spine, 53 lumbar spine, and 1 sacral spine) were treated in 104 patients. The median follow-up was 14.5 months (range 0.4-109). Local progression occurred in 10 patients (10 vertebrae) after a median time of 22.3 months (range 1.5-73) resulting in local control rates of 97.1, 95.9, and 94.2% at 6, 12, and 24 months, respectively. Overall survival was 74.6, 61.7, and 50.3% at 6, 12, and 24 months, respectively. A single serious adverse event was reported. CONCLUSION: In addition to immediate pain reduction and stabilization, Kypho-IORT shows excellent long-term local control with minimal side effects.

S100B Serum Level is Independent of Moderate Alcohol Intoxication. / S100B-Serumniveau ist unabhängig von moderatem Alkoholkonsum.

OBJECTIVE: In Germany, among patients with minor head injury (MHI), the incidence of coexisting alcohol intoxication is indicated up to 50%. The neurological symptoms of patients with MHI may be caused or altered by alcohol intoxication, this could mislead to further, potential harmful, diagnostic steps or to misinterpretation of the symptoms and to non-execution of necessary treatments. In order to decide which patients need further diagnostics by CCT, S100B has been proposed as a potential selection criterion. On the other hand, studies have hypothesized that alcohol intoxication may lead to elevated S100B serum levels. Therefore, the present study aims to investigate the relationship between the blood ethyl alcohol concentration and the S100B serum concentration in an experimental setting in young human adult volunteers. METHODS: In a cohort of 58 healthy volunteers, serum S100B concentration and blood ethyl alcohol concentration were measured before and after liberately drinking alcohol. The study was approved by the local Ethics Committee of the Medical Faculty Mannheim (Ethics Committee II, AZ 2012-272 N-MA). Instantaneous analysis of the samples was carried out using state-of-the art automated measuring systems. (Analyzer Cobas e411, Roche and Analyzer Dimension Vista 1500, Siemens). RESULTS: After drinking, alcohol levels ranged from 0,23 to 1,92 g/l. The S100B value ranged from to 0,021 to 0,115 µg/l after alcohol consumption (S100B standard value < 0,11 µg/l). By calculating the Pearson correlation of empirical correlation after drinking alcohol with r = 0.01181, a correlation between serum S100B concentration and ethyl alcohol concentration is not probable. The S100B concentrations were independent on the alcohol intake in low to medium alcohol levels. CONCLUSION: A relevant alcohol blood concentration (~ 1 g/l), in otherwise healthy volunteers, does not affect the serum concentration of S100B. S100B may be a useful brain injury marker in low to moderate drunken patients.

Scientific Backgrounds for the Timing of Acute Care Surgery. / Die wissenschaftlichen Grundlagen der OP-Indikationen (Dringlichkeit/Notfall).

The correct timing of urgent surgery in the field of orthopedic and trauma surgery is under constant discussion. The authors of this review like to present a scientific based recommendation for the timing of acute care surgery using the TACS-classification for the description of urgency. The timing and priority of the indicated procedure is deduced only from the expected mortality and disability caused by a potential delay. A proposal for a nomenclature is given to be integrated in the clinical practice and to be completed.

Report on a large animal study with Göttingen Minipigs where regenerates and controls for articular cartilage were created in a large number. Focus on the conditions of the operated stifle joints and suggestions for standardized procedures.

The characterization of regenerated articular cartilage (AC) can be based on various methods, as there is an unambiguous accepted criterion neither for the natural cartilage tissue nor for regenerates. Biomechanical aspects should be considered as well, leading to the need for more equivalent samples. The aim of the study was to describe a large animal model where 8 specimens of regenerated AC can be created in one animal plus the impact of two surgeries on the welfare of the animals. The usefulness of the inclusion of a group of untreated animals (NAT) was to analyzed. Based on the histological results the conditions of the regenerates were to be described and the impact on knee joints were to be explored in terms of degenerative changes of the cartilage. The usefulness of the statistical term "effect size" (ES) will be explained with histological results. We analyzed an animal model where 8 AC regenerates were obtained from one Göttingen Minipig, on both sides of the trochleae. 60 animals were divided into 6 groups of 10 each, where the partial thickness defects in the trochlea were filled with matrices made of Collagen I with or without autologous chondrocytes or left empty over the healing periods of 24 and 48 weeks. One additional control group consisting of 10 untreated animals was used to provide untouched "external" cartilage. We harvested 560 samples of regenerated tissue and "external" controls, besides that, twice the number of further samples from other parts of the joints referred to as "internal" controls were also harvested. The animals recovered faster after the 1st operation when the defects were set compared to the 2nd operation when the defects were treated. 9% of all animals were lost. Other complications were for example superficial infections, seroma, diarrhea, febrile state and an injury of a claw. The histological results of the treatments proved the robustness of the study design where we included an "external" control group (NAT) in which the animals were not operated. Comparable significant differences between treated groups and the NAT group were detected both after ½ year and after 1 year. Spontaneous regenerated AC as control revealed differences after an observation time of nearly 1 year. The impact of the treatment on cartilage adjacent to the defect as well as the remaining knee joint was low. The ES was helpful for planning the study as it is shown that the power of a statistical comparison seems to be more influenced by the ES than by the sample size. The ranking of the ES was done exemplarily, listing the results according to their magnitude, thus making the results comparable. We were able to follow the 3 R requirements also in terms of a numerical reduction of animals due to the introduction of a group of untreated animals. This makes the model cost effective. The presented study may contribute as an improvement of the standardization of large animal models for research and regulatory requirements for regenerative therapies of AC.

Combined kyphoplasty and intraoperative radiotherapy (Kypho-IORT) versus external beam radiotherapy (EBRT) for painful vertebral metastases - a randomized phase III study.

BACKGROUND: The spine is the most frequent location of bone metastases. Local treatment aims at palliation of pain and, given the increased likelihood of long-term cancer survival, at local control. Kyphoplasty and intraoperative radiotherapy (Kypho-IORT) provided instantaneous pain relief in 70% of patients at the first day after the intervention and resulted in local control rates of > 93% at 1 year in a recently conducted phase I/II trial. To assess its clinical value, we designed a phase III trial which tests Kypho-IORT against the most widespread standard-of-care, external beam radiotherapy (EBRT), in patients with painful vertebral metastases. METHODS: This phase III study includes patients ≥50 years of age with up to 4 vertebral metastases and a pain score of at least 3/10 points on the visual/numeric analogy scale (VAS). Patients randomized into the experimental arm (A) will undergo Kypho-IORT (Kyphoplasty plus IORT with 8 Gy prescribed to 13 mm depth). Patients randomized into the control arm (B) will receive EBRT with either 30 Gy in 10 fractions or 8 Gy as a single dose. The primary end point is pain reduction defined as at least - 3 points on the VAS compared to baseline at day 1. Assuming that 40% of patients in the Kypho-IORT arm and 5% of patients in the control arm will achieve this reduction and 20% will drop out, a total of 54 patients will have to be included to reach a power of 0.817 with a two-sided alpha of 0.05. Secondary endpoints are evaluation of the percentage of patients with a pain reduction of at least 3 points at 2 and 6 weeks, local tumor control, frequency of re-intervention, secondary fractures/sintering, complication rates, skin toxicity/wound healing, progression-free survival (PFS), overall survival (OS) and quality of life. DISCUSSION: This trial will generate level 1 evidence on the clinical value of a one-stop procedure which may provide instantaneous pain relief, long-term control and shortened intervals to further adjuvant (systemic) therapies in patients with spinal metastases. TRIAL REGISTRATION: Registered with ClinicalTrials.gov, number: NCT02773966 (Registration date: 05/16/2016).

Usefulness of slice encoding for metal artifact correction (SEMAC) technique for reducing metal artifacts after total knee arthroplasty.

PURPOSE: To evaluate the usefulness of a novel MRI sequence strategy in the assessment of the periprosthetic anatomical structures after primary total knee arthroplasty. METHODS: Two MR sequences were retrospectively compared for the imaging of 15 patients with implanted cruciate-retaining/fixed-bearing TKAs (DePuy, PFC Sigma): a slice encoding sequence for metal artifact correction (SEMAC) and a standard sequence. Images were acquired on a 1.5-T system. The degree of artifact reduction was assessed using several qualitative (Likert-type scale) (artifact size, distorsion, blur, image quality, periprosthetic bone, posterior cruciate ligament, lateral collateral ligament, medial collateral ligament, patella tendon, popliteal vessels) and quantitative (artifact volume, Insall-Salvati index, length of patella/tendon, prosthesis dimensions) parameters by blinded reads performed by four investigators. The SEMAC sequences were statistically compared with the standard sequence using Wilcoxon test. Additionally, the intraclass correlation coefficient (ICC) for interobserver agreement was calculated. RESULTS: Higher levels of blurring were found with SEMAC compared to standard sequences (p < 0.001). All other qualitative parameters improved significantly with the application of SEMAC. In comparison with conventional sequences, the artifact volume was reduced by 59% utilizing SEMAC. Thus, the artifact reduction improved the precision of measurements such as Insall-Salvati index and length of patella/tendon (p < 0.001). The dimension of the tibial component (Ti alloy/polyethylene) revealed accurate values with both MRI sequences. A sufficient interobserver agreement among all readers was found with SEMAC, qualitatively ICC 0.9 (range 0.8-1) as well as quantitatively ICC 0.95 (range 0.92-0.98). CONCLUSIONS: SEMAC effectively reduces artifacts caused by metallic implants after total knee arthroplasty relative to standard imaging. This allows for an improved assessment of periprosthetic anatomical structures. This might enable an improved detectability of postoperative complications in the future. LEVEL OF EVIDENCE: Diagnostic Study Level III.

Cuboid nutcracker fracture in children: Management and results.

INTRODUCTION: Compression fractures of the cuboid bone in children and adolescents are rare. Fracture morphology, associated lesions, treatment options and long-term outcomes of this very rare injury are published in a few case reports. This study with review of the literature aims to support the understanding of fracture pattern and optimize pathways of decision making. MATERIAL AND METHODS: A retrospective two-center study was performed in a patient cohort treated between 2001 and 2016. All patients aged less than 18 years who sustained a cuboid fracture were included. Age, gender, mechanism of injury, fracture morphology, amount of displacement, associated injuries, and therapy were analyzed. In the follow-up (FU), the AOFAS Midfoot Scale was investigated. RESULTS: Fractures of the cuboid bone were diagnosed in 7 boys and 9 girls. The mean age of the patients was 10 years (range: 2.2-16.1 years). According to the classification of Fenton we detected 11 (69%) type 2, 2 (12%) type 3 and 3 (19%) type 5b fractures. Other fracture types according to Fenton were not observed. All children under 10 years sustained a type 2 fracture. Open reduction and internal fixation was performed in 5 (31%) patients. Bone grafting was not necessary. FU was performed in 14/16 patients on average after 9 years (mean; range: 1.4-16.2 years). The mean AOFAS Midfoot Scale at FU for extra-articular type 2 fractures was 100 points, whereas in intra-articular fractures (Type 3) and fractures associated with mid-tarsal disruption (type 5b) worse results were found (95 and 66 points, accordingly). CONCLUSION: This rare injury shows inhomogenous morphologies and offers different treatment approaches. Extra-articular Fenton type 2 lesions are the most common type of cuboid fracture in children (69%). A potential loss of length of the lateral column must be considered. In contrast to adults, type 1, 4, and 5a fractures were not found in our cohort of children and adolescents. Lower scores of the AOFAS Midfoot Scale were found with either intra-articular involvement or associated midfoot lesions.

Avulsion fracture of the lesser trochanter in adolescents.

INTRODUCTION: Avulsion fractures of the lesser trochanter in adolescents are rare. They are a result of a sudden and forceful contraction of the iliopsoas muscle. Functional results in the medium term after non-operative treatment are unknown. Therefore we aimed to report these in the present study. MATERIALS AND METHODS: A retrospective two-center study was performed in a case series treated between 2011 and 2017. All adolescents with an acute avulsion fracture of the lesser trochanter were included. Age, gender, mechanism of injury, fracture side, amount of displacement, and therapy were analyzed. In the follow-up, the Harris Hip Score (HHS), the sports level, the power of flexion in the hip, and signs of an ischio-femoral impingement (IFI) were investigated. RESULTS: An avulsion fracture of the lesser trochanter was diagnosed in 4 boys and 1 girl. The mean age of the patients was 13.8 years (range: 13-15 years). We observed 2 type II and 3 type III fractures. The patients received similar non-operative treatment. Follow-up was performed at a mean of 4.9 years (range: 3.5-6.2 years) after injury. All patients returned to competitive sports. The Harris Hip Score (HHS) was 100 out of 100 points. History and provocation test concerning an IFI were negative in all patients. CONCLUSION: Our study shows excellent results with non-operative treatment in acute avulsion fractures of the lesser trochanter in a case series of five adolescents. All patients returned to competitive sports. In our opinion, acute avulsion fractures of the lesser trochanter should be treated non-operatively.

Phase I/II trial of combined kyphoplasty and intraoperative radiotherapy in spinal metastases.

BACKGROUND CONTEXT: Spinal metastases occur in 30%-50% of patients with systemic cancer. The primary goals of palliation are pain control and prevention of local recurrence. PURPOSE: This study aimed to test the safety and efficacy of a combined modality approach consisting of kyphoplasty and intraoperative radiotherapy (Kypho-IORT). STUDY DESIGN/SETTING: Kyphoplasty and intraoperative radiotherapy was a prospective, single-center phase I/II trial. Patients were enrolled in a classical 3+3 scheme within the initial phase I, where Kypho-IORT was applied using a needle-shaped 50 kV X-ray source at three radiation dose levels (8 Gy in 8-mm, 8 Gy in 11-mm, and 8 Gy in 13-mm depth). Thereafter, cohort expansion was performed as phase II of the trial. The trial is registered with clinicaltrials.gov, number NCT01280032. PATIENT SAMPLE: Patients aged 50 years and older with a Karnofsky Performance Status of at least 60% and with one to three painful vertebral metastases confined to the vertebral body were eligible to participate. OUTCOME MEASURES: The primary end point was safety as per the occurrence of dose-limiting toxicities. The secondary end points were pain reduction, local progression-free survival (L-PFS), and overall survival (OS). METHODS: Pain was measured using the visual analog scale (VAS) and local control was assessed in serial computed tomography or magnetic resonance imaging scans. RESULTS: None of the nine patients enrolled in the phase I showed dose-limiting toxicities at any level and thus, 52 patients were subsequently enrolled into a phase II, where Kypho-IORT was performed at various dose levels. The median pain score significantly dropped from 5 preoperatively to 2 at the first postoperative day (p<.001). Of 43 patients who reported a pre-interventional pain level of 3 or more, 30 (69.8%) reported a reduction of ≥3 points on the first postoperative day. A persistent pain reduction beyond the first postoperative day of ≥3 points was seen in 34 (79.1%) patients. The 3, 6, and 12 month L-PFS was excellent with 97.5%, 93.8%, and 93.8%. The 3, 6, and 12 months OS was 76.9%, 64.0%, and 48.4%. CONCLUSION: Kyphoplasty and intraoperative radiotherapy is safe and immediately provided sustained pain relief with excellent local control rates in patients with painful vertebral metastases.

Combined stereotactic biopsy and stepping-source interstitial irradiation of glioblastoma multiforme.

Patients diagnosed with glioblastoma multiforme receiving stereotactic biopsy only either due to tumor localization or impaired clinical status face a devastating prognosis with very short survival times. One strategy to provide an initial cytoreductive and palliative therapy at the time of the stereotactic biopsy is interstitial irradiation through the pre-defined trajectory of the biopsy channel. We designed a novel treatment planning system and evaluated the treatment potential of a fixed-source and a stepping-source algorithm for interstitial radiosurgery on non-spherical glioblastoma in direct adjacency to risk structures. Using both setups, we show that radiation doses delivered to 100% of the gross tumor volume shifts from sub-therapeutic (10-12 Gy) to sterilizing single doses (25-30 Gy) when using the stepping source algorithm due to improved sparing of organs-at-risk. Specifically, the maximum doses at the brain stem were 100% of the PTV dose when a fixed central source and 38% when a stepping-source algorithm was used. We also demonstrated precision of intracranial target points and stability of superficial and deep trajectories using both a phantom and a body donor study. Our setup now for the first time provides a basis for a clinical proof-of-concept trial and may widen palliation options for patients with limited life expectancy that should not undergo time-consuming therapies.

Circulating Tumour Cell Release after Cement Augmentation of Vertebral Metastases.

Cement augmentation via percutaneous vertebroplasty or kyphoplasty for treatment of spinal metastasis is a well-established treatment option. We assessed whether elevated intrametastatic pressure during cement augmentation results in an increased dissemination of tumour cells into the vascular circulation. We prospectively collected blood from patients with osteolytic spinal column metastases and analysed the prevalence of circulating tumour cells (CTCs) at three time-points: preoperatively, 20 minutes after cement augmentation, and 3-5 days postoperatively. Enrolling 21 patients, including 13 breast- (61.9%), 5 lung- (23.8%), and one (4.8%) colorectal-, renal-, and prostate-carcinoma patient each, we demonstrate a significant 1.8-fold increase of EpCAM+/K+ CTCs in samples taken 20 minutes post-cement augmentation (P < 0.0001). Despite increased mechanical CTC dissemination due to cement augmentation, follow-up blood draws demonstrated that no long-term increase of CTCs was present. Array-CGH analysis revealed a specific profile of the CTC collected 20 minutes after cement augmentation. This is the first study to report that peripheral CTCs are temporarily increased due to vertebral cement augmentation procedures. Our findings provide a rationale for the development of new prophylactic strategies to reduce the increased release of CTC after cement augmentation of osteolytic spinal metastases.

Precision IORT - Image guided intraoperative radiation therapy (igIORT) using online treatment planning including tissue heterogeneity correction.

BACKGROUND: To the present date, IORT has been eye and hand guided without treatment planning and tissue heterogeneity correction. This limits the precision of the application and the precise documentation of the location and the deposited dose in the tissue. Here we present a set-up where we use image guidance by intraoperative cone beam computed tomography (CBCT) for precise online Monte Carlo treatment planning including tissue heterogeneity correction. MATERIALS AND METHODS: An IORT was performed during balloon kyphoplasty using a dedicated Needle Applicator. An intraoperative CBCT was registered with a pre-op CT. Treatment planning was performed in Radiance using a hybrid Monte Carlo algorithm simulating dose in homogeneous (MCwater) and heterogeneous medium (MChet). Dose distributions on CBCT and pre-op CT were compared with each other. Spinal cord and the metastasis doses were evaluated. RESULTS: The MCwater calculations showed a spherical dose distribution as expected. The minimum target dose for the MChet simulations on pre-op CT was increased by 40% while the maximum spinal cord dose was decreased by 35%. Due to the artefacts on the CBCT the comparison between MChet simulations on CBCT and pre-op CT showed differences up to 50% in dose. CONCLUSIONS: igIORT and online treatment planning improves the accuracy of IORT. However, the current set-up is limited by CT artefacts. Fusing an intraoperative CBCT with a pre-op CT allows the combination of an accurate dose calculation with the knowledge of the correct source/applicator position. This method can be also used for pre-operative treatment planning followed by image guided surgery.

Radiation protection for an intraoperative X-ray source compared to C-arm fluoroscopy.

BACKGROUND: Intraoperative radiotherapy (IORT) using the INTRABEAM(®) system promises a flexible use regarding radiation protection compared to other approaches such as electron treatment or HDR brachytherapy with (192)Ir or (60)Co. In this study we compared dose rate measurements of breast- and Kypho-IORT with C-arm fluoroscopy which is needed to estimate radiation protection areas. MATERIALS AND METHODS: C-arm fluoroscopy, breast- and Kypho-IORTs were performed using phantoms (silicon breast or bucket of water). Dose rates were measured at the phantom's surface, at 30 cm, 100 cm and 200 cm distance. Those measurements were confirmed during 10 Kypho-IORT and 10 breast-IORT patient treatments. RESULTS: The measured dose rates were in the same magnitude for all three paradigms and ranges from 20 µSv/h during a simulated breast-IORT at two meter distance up to 64 mSv/h directly at the surface of a simulated Kypho-IORT. Those measurements result in a circle of controlled area (yearly doses >6 mSv) for each paradigm of about 4 m±2 m. DISCUSSION/CONCLUSIONS: All three paradigms show comparable dose rates which implies that the radiation protection is straight forward and confirms the flexible use of the INTRABEAM(®) system.

Intraoperative radiotherapy during kyphoplasty for vertebral metastases (Kypho-IORT): first clinical results.

AIMS AND BACKGROUND: Kyphoplasty is an effective procedure providing structural stability and pain alleviation in vertebral metastases. To prevent early regrowth, patients typically receive postoperative fractionated radiotherapy, which is associated with long treatment duration. Therefore, we established a new approach to deliver intraoperative radiotherapy during kyphoplasty to shorten the treatment time and reach structural stability and sterilization of the metastases (Kypho-IORT). METHODS AND STUDY DESIGN: For Kypho-IORT, a 50 kV X-ray source with a specially designed applicator was used. A radiation dose of 8 Gy in 5 mm distance was delivered. After radiation the device was removed and the kyphoplasty was completed according to the standard procedure. Since August 2009, 18 patients with instable or painful spinal metastases received Kypho-IORT. The median age was 63 years (range, 43-73). RESULTS: Kypho-IORT was successfully performed in 18 of 21 vertebral lesions (86%). No severe complications occurred during or early after IORT. The median pain score using a visual analogue scale decreased from 5/10 before the procedure to 2.5/10 at day 1 (P <0.001) and to 0/10 six weeks after the procedure (P = 0.001). Imaging studies were available for 15 of 18 patients. Stable disease within the irradiated vertebral body was seen in 14 patients (93%) and local progressive disease in one patient (7%). No re-irradiation due to local progressive disease or pain recurrence was necessary within the median follow-up of 4.5 months. CONCLUSIONS: Kypho-IORT is well tolerated without severe side effects and provides fast improvement of pain. Although stable disease was seen in 93% of the patients, a longer follow-up is necessary to assess the effectiveness. A dose escalation study to establish the maximally tolerated dose has been initiated.

Kyphoplasty and intra-operative radiotheray, combination of kyphoplasty and intra-operative radiation for spinal metastases: technical feasibility of a novel approach.

PURPOSE: To evaluate whether this new method is clinically applicable after theoretical and cadaver testing. METHODS: The incidence of spinal metastases requiring therapy is increasing, due to enhanced life expectancy. Due to results from studies with epidural compression a combined surgical and radiation therapy is often chosen. Minimal invasive cement augmentation is an increasingly used technique, due to fast pain relief and immediate stabilisation. On the other hand, stereotactic radiosurgery is considered to provide a more durable response and better local disease control than conventional radiotherapy with the application of higher doses. Therefore the combination of cement stabilisation and simultaneous intra-operative radiation with immediate stabilisation and high-dose radiation could be an interesting therapeutic option. The results of a clinical feasibility study are presented. RESULTS: 17 patients could be treated with the new method. In two patients (10%) intra-operative radiation could not be applied. No surgical interventions for complications were required. CONCLUSIONS: Summarizing Kypho-IORT is technically feasible with an intra-operative risk profile comparable to sole kyphoplasty and a shorter treatment time and hospitalisation for the patients compared to conventional multifraction radiation. Radiation could not be applied in 10% of cases due to technical difficulties. The results of this feasibility study permit further evaluation of this new technique by a dose escalation study which is currently in preparation.