Minimally Invasive Transforaminal Lumbar Interbody Fusion Using Augmented Reality Surgical Navigation for Percutaneous Pedicle Screw Placement.

STUDY DESIGN: This was a retrospective observational study. OBJECTIVE: The aim of this study was to evaluate the accuracy of percutaneous pedicle screw placement using augmented reality surgical navigation during minimally invasive transforaminal lumbar interbody fusion (TLIF). SUMMARY OF BACKGROUND DATA: Augmented reality-based navigation is a new type of computer-assisted navigation where video cameras are used instead of infrared cameras to track the operated patients and surgical instruments. This technology has not so far been clinically evaluated for percutaneous pedicle screw placement. MATERIALS AND METHODS: The study assessed percutaneous pedicle screw placement in 20 consecutive patients who underwent single-level minimally invasive TLIF using augmented reality surgical navigation. Facet joint violation and depression by the inserted pedicle screws were evaluated. Secondary outcome such as radiation dose exposure, fluoroscopy time, and operative time were collected for 3 phases of surgery: preparation phase, pedicle screw placement, and decompression with cage placement. RESULTS: A clinical accuracy for screw placement within the pedicle (Gertzbein 0 or 1) of 94% was achieved. One screw violated the facet joint with a transarticular pathway. The screw head did not depress the facet in 54%. The use of fluoroscopy during navigation correlated with patient body-mass index (r=0.68, P<0.0001). The pedicle screw placement time corresponded to 36±5% of the total operative time of 117±11 minutes. A statistically significant decrease of 10 minutes in operative time was observed between the first and last 10 procedures which corresponded to the pedicle screw placement time decrease (48±9 vs. 38±7 min, P=0.0142). The learning curve model suggests an ultimate operative time decrease to 97 minutes. CONCLUSION: Augmented reality surgical navigation can be clinically used to place percutaneous screws during minimally invasive TLIF. However, the lack of tracking of the location of the device requires intraoperative fluoroscopy to monitor screw insertion depth especially in obese patients. LEVEL OF EVIDENCE: Level III.

Percutaneous thermal ablation of sacral metastases: Assessment of pain relief and local tumor control.

PURPOSE: To retrospectively report on safety, pain relief and local tumor control achieved with percutaneous ablation of sacral bone metastases. MATERIALS AND METHODS: From February 2009 to June 2020, 23 consecutive patients (12 women and 11 men; mean age, 60±8 [SD] years; median, 60; range: 48-80 years) with 23 sacral metastases underwent radiofrequency (RFA) or cryo-ablation (CA), with palliative or curative intent at our institution. Patients' demographics and data pertaining to treated metastases, procedure-related variables, safety, and clinical evolution following ablation were collected and analyzed. Pain was assessed with numerical pain rating scale (NPRS). RESULTS: Sixteen (70%) patients were treated with palliative and 7 (30%) with curative intent. Mean tumor diameter was 38±19 (SD) mm (median, 36; range: 11-76). External radiation therapy had been performed on five metastases (5/23; 22%) prior to ablation. RFA was used in 9 (39%) metastases and CA in the remaining 14 (61%). Thermo-protective measures and adjuvant bone consolidation were used whilst treating 20 (87%) and 8 (35%) metastases, respectively. Five (22%) minor complications were recorded. At mean 31±21 (SD) (median, 32; range: 2-70) months follow-up mean NPRS was 2±2 (SD) (median, 1; range: 0-6) vs. 5±1 (median, 5; range: 4-8; P<0.001) at the baseline. Three metastases out of 7 (43%) undergoing curative ablation showed local progression at mean 4±4 (SD) (median, 2; range: 1-8) months follow-up. CONCLUSION: Percutaneous ablation of sacral metastases is safe and results in significant long-lasting pain relief. Local tumor control seems sub-optimal; however, further investigations are needed to confirm these findings due to paucity of data.

Complications of percutaneous image-guided screw fixation: An analysis of 94 consecutive patients.

PURPOSE: The purpose of this study was to retrospectively assess the safety profile of percutaneous image-guided screw fixation (PIGSF) for insufficiency, impending or pathological fractures. MATERIALS AND METHODS: From July 2012 to April 2020, all consecutive patients who underwent PIGSF were retrospectively included in the study. Patient characteristics, fracture type, procedural data and complications were analyzed. Complications were divided into per-procedural, early (<24hours) and delayed (>24hours) and classified into minor (grade 1-2) and major complications (grade 3-5) according to Common Terminology Criteria for Adverse Events (CTCAE) v5.0. RESULTS: A total of 110 fractures (40 insufficiency [36%], 53 pathological [48.5%] and 17 impending [15.5%] fractures) in 94 patients (48 women, 46 men; mean age, 62.7±12.7 [SD] years; age range: 32-88 years) were treated with PIGSF during 95 procedures. Twenty-four-hours follow-up was available for all patients, and>24-hours follow-up was available for 79 (79/110; 71.8%) fractures in 69 (69/94; 73.4%) patients. Per-procedural complications occurred in 3/110 fractures (2.7%, all minor). Early complications were reported in 4/110 fractures (3.6%, 1 major and 3 minor) and delayed ones in 14/79 fractures (17.7%, 5 major and 9 minor). The most frequent major delayed complication was infection (3/79; 3.8%). CONCLUSION: The rate of per-procedural and early (within 24hours) complications following PIGSF is extremely low with most complications being minor, with major complications being delayed ones (>24hours).

Performance of a New Blunt-Tip Needle for the Displacement of Critical Structure in Thermal Ablation.

PURPOSE: To ascertain the performance of a new blunt-tip needle (HydroGuard®), which allows injection of fluids during needle advancement in order to safely approach, displace and insulate nearby critical structures during thermal ablation (TA). MATERIALS AND METHODS: This study included 27 consecutive patients treated by TA [cryoablation (CA), radiofrequency (RFA), and microwave MWA)] between April 2018 and January 2019. During TA, hydro- or gas dissection was performed with HydroGuard® needle to displace and protect critical structures close to the tumor (< 10 mm). Technical and clinical success, distance between critical structure and tumor before and after hydro/gas dissection and complications were recorded. RESULTS: Eighteen patients were treated by CA (66.7%), 7 by MWA (25.9%) and 2 by RFA (7.4%). Majority of patients were treated with a curative intent (24/27; 88.8%). Adjacent critical structures include vessels (n = 3), nerves (n = 10), ureter/renal pelvis (n = 3), bowel/rectum (n = 10), stomach: (n = 3), diaphragm (n = 2), and pleura (n = 1). Technical success was 100%. Clinical success was 88% (24/27). Median minimum distance to adjacent critical structures before hydro/gas dissection was 1 mm (range 0-9 mm; IQR: 0-3 mm) versus 10.5 mm (range 4-47 mm; IQR: 9.7-18 mm) after displacement. Of the 27 patients treated, four developed complications (14.8%; 95% CI: 1.4-28.2): 1 major (3.7%; 95% CI: 0-10.8) and 3 minors (11.1%; 95% CI: 0-23). Only one minor complication was related to inadequate hydro-dissection, resulting in close proximity of the critical structure to the ablation zone. CONCLUSION: HydroGuard® is a safe and effective needle when used to approach, displace and insulate nearby critical structures during TA.

Complications of Percutaneous Bone Tumor Cryoablation: A 10-year Experience.

Background Percutaneous cryoablation has been shown to be effective in the management of painful bone tumors. However, knowledge of the complication rate and risk factors for complication is currently lacking. Purpose To report the complication rate and associated risk factors for bone tumor cryoablation. Materials and Methods This retrospective study reviewed complications in 239 consecutive patients (131 men and 108 women; median age, 64 years; age range, 6-86 years) who underwent cryoablation of 320 primary or metastatic bone tumors between January 2008 and November 2017. Common Terminology Criteria for Adverse Events was used to categorize complications as major (grade 3-4) or minor (grade 1-2). Multivariable analysis was performed for variables with P values less than .20, including age, tumor location, adjacent critical structures, number of cryoprobes, and Eastern Cooperative Oncology Group performance status (ECOG-PS). Results Among the 320 tumors, the total complication rate was 9.1% (29 of 320; 95% confidence interval [CI]: 6%, 12.2%). The major complication rate was 2.5% (eight of 320; 95% CI: 0.8%, 4.2%), with secondary fracture the most frequent complication (1.2% [four of 320]; mean delay, 71 days); cryoablation site infection, tumor seeding, bleeding, and severe hypotension were each observed in 0.3% (one of 320) of procedures. Minor complications included postprocedural pain (2.2% [seven of 320]), peripheral neuropathy (0.9% [three of 320]), and temporary paresthesia (0.9% [three of 320]). For all complications, associated risk factors included ECOG-PS greater than 2 (odds ratio [OR], 3.1 [95% CI: 3, 7.6]; P = .01), long-bone cryoablation (OR, 17.8 [95% CI: 2.3, 136.3]; P = .01), and use of more than three cryoprobes (OR, 2.5 [95% CI: 1.0, 6.0]; P = .04); for major complications, associated risk factors included age greater than 70 years (OR, 7.1 [95% CI: 1.6, 31.7]; P = .01) and use of more than three cryoprobes (OR, 23.6 [95% CI: 2.8, 199.0]; P = .01). Conclusion Bone tumor cryoablation is safe, with a 2.5% rate of major complications, most commonly secondary fracture (1.2%). Major complications are associated with age greater than 70 years and use of more than three cryoprobes. © RSNA, 2019 Online supplemental material is available for this article. See also the editorial by Jennings in this issue.

Present role and future perspectives of interventional radiology in the treatment of painful bone lesions.

Interventional radiology has experienced an exponential growth in the last years. Nowadays it is possible to treat painful benign lesions or metastases with optimal results in terms of pain management and disease control. Among the benign lesions, osteoid osteoma is the most frequently treated with minimal invasive techniques and the results are excellent. Another lesion, traditionally treated with surgery (osteoblastoma) represent today another field of application. In the oncological field, metastases are, numerically, the most diffuse indications for treatment. Research carried out during the last decades has provided the interventional radiologist with a great variety of techniques of ablation and devices for monitoring the sensitive structures close to the target lesion. New ablation techniques and monitoring devices contribute to the achievement of significantly increasing rates of effectiveness and safety of interventional radiology procedures.

Protection of the Proximal Articular Cartilage During Percutaneous Thermal Ablation of Acetabular Metastasis Using Temperature Monitoring.

OBJECTIVE: To review our initial experience in acetabular cartilage protection from thermal injury with temperature monitoring during percutaneous image-guided tumor thermal ablation. MATERIALS AND METHODS: Between June 2015 and December 2016, three consecutive oncologic patients (mean age 58 years; range 48-67 years) with acetabular bone metastasis underwent percutaneous image-guided thermal ablation procedures along with hip joint cartilage thermal monitoring. Due to the close proximity of the metastatic lesion to the acetabular articular cartilage, a thermosensor device was placed under CT and fluoroscopic guidance near the acetabular roof and next to the ablation zone in order to monitor the local temperature around the articular cartilage. Stand-alone thermal ablation (n = 1) and combined thermal ablation with cementoplasty (n = 2) were performed to optimize local palliation or disease control. Clinical and radiological outcomes at follow-up were assessed. RESULTS: Three acetabular metastatic lesions were treated with thermal ablation, and temperature monitoring of the acetabular articular cartilage was conducted during the ablation procedure. Mean size of lesions was 1.6 cm (range 1.5-2 cm). Technical success was achieved in all cases (100%) without any immediate complications. No hip cartilage damage occurred clinically and radiologically. Good palliation and local disease control were achieved in two cases, and in the other case, there was local recurrence and distant progression of hip metastatic disease after 7 months of follow-up. CONCLUSION: Temperature monitoring of the articular cartilage during percutaneous image-guided thermal ablation appears technically feasible with good short-term efficacy in a complex patient subset. Further studies are warranted to confirm these promising initial results.

Cryoablation of lung malignancies recurring close to surgical clips following surgery: Report of three cases.

BACKGROUND: Minimally ablative therapies are now available for the treatment of lung malignancies. However, selection of the appropriate technique is not always easy and requires accurate preoperative planning. AIMS: To describe the treatment of lung tumors with cryoablation. SETTINGS AND DESIGN: We report three cases of lung malignancies that recurred close to surgical clips after surgical treatment, successfully treated by cryoablation. MATERIALS AND METHODS: An initial freezing cycle was performed for 10 min, followed by a 5-min thawing cycle, and an additional 10-min freezing cycle. A final 5-min thaw was necessary to remove the needle from the iceball formed during the freezing cycle. RESULTS: The procedures were completed successfully with no signs of surgical-clip misplacement, and excellent ablation of the lesions. CONCLUSION: Cryoablation is a relatively new procedure that potentially permits the local treatment of lung tumors with minimal loss of lung parenchyma.

Temperature monitoring and lesion volume estimation during double-applicator laser-induced thermotherapy in ex vivo swine pancreas: a preliminary study.

Tissue temperature distribution plays a crucial role in the outcome of laser-induced thermotherapy (LITT), a technique employed for neoplasias removal. Since recent studies proposed LITT for pancreatic tumors treatment, assessment of temperature and of its effects around the laser applicator could be useful to define optimal laser settings. The aims of this work are temperature monitoring and measurement of ablated tissue volume in an ex vivo porcine pancreas undergoing double-applicator LITT. A three-dimensional numerical model is implemented to predict temperature rise and volumes of ablated tissue in treated pancreas. Experiments are performed to validate the model, with two modalities: (1) 12-fiber Bragg grating sensors are adopted to monitor the heating and cooling during LITT at several distances from the applicators tip, and (2) 1.5-T MR imaging is used to estimate the ablated volume. Experimental data agree with theoretical ones: at 2 mm from both applicators tips, the maximum temperature increase is approximately 60 °C downward from the tips, while it increases of about 40 °C and 30 °C, respectively, at the level and upward from the tips. This behavior occurs also at other distances, proving that the tissue downward from the tip is mostly heated. Furthermore, the estimated volume with MRI agrees with theoretical one (i.d., 0.91 ± 0.09 vs. 0.95 cm(3)). The encouraging results indicate that the model could be a suitable tool to choose the optimal laser settings, in order to control the volume of ablated tissue.

Herlyn-Werner-Wunderlich syndrome: MRI findings, radiological guide (two cases and literature review), and differential diagnosis.

BACKGROUND: Herlyn-Werner-Wunderlich (HWW) syndrome is a very rare congenital anomaly of the urogenital tract involving Müllerian ducts and Wolffian structures, and it is characterized by the triad of didelphys uterus, obstructed hemivagina and ipsilateral renal agenesis. It generally occurs at puberty and exhibits non-specific and variable symptoms with acute or pelvic pain shortly following menarche, causing a delay in the diagnosis. Moreover, the diagnosis is complicated by the infrequency of this syndrome, because Müllerian duct anomalies (MDA) are infrequently encountered in a routine clinical setting. CASES PRESENTATION: two cases of HWW syndrome in adolescents and a differential diagnosis for one case of a different MDA, and the impact of magnetic resonance (MR) imaging technology to achieve the correct diagnosis. CONCLUSIONS: MR imaging is a very suitable diagnostic tool in order to perform the correct diagnosis of HWW syndrome.