Sparing Adjacent Structures Research Articles

Pulsed Field Ablation of Atrial Fibrillation: A Comprehensive Review.

Pulsed-field ablation (PFA) has emerged as a promising nonthermal ablation alternative for treating atrial fibrillation (AF). By delivering ultra-rapid high-energy electrical pulses, PFA induces irreversible electroporation, selectively targeting myocardial tissue while sparing adjacent structures from thermal or other damage. This article provides a comprehensive review of multiple pre-clinical studies, clinical studies, and clinical trials evaluating the safety, efficacy, and long-term outcomes of PFA in various settings and patient populations. Overall, the reviewed evidence highlights PFA's potential as a revolutionary ablation strategy for AF treatment. Offering comparable procedural efficacy to conventional ablation methods, PFA distinguishes itself with shorter procedure times and reduced risks of complications such as phrenic nerve palsy and potential esophageal injury. While further research is warranted to establish long-term efficacy, PFA's distinct advantages and evolving clinical evidence suggest a promising future for this novel nonthermal ablation approach. As PFA continues to advance, it has the potential to transform AF ablation procedures, providing a safer alternative for patients with atrial fibrillation.

Intraoperative radiation therapy for high risk soft tissue sarcoma resection margins

Background and objectives: External beam radiation (EBRT) can reduce local recurrence (LR) of soft tissue sarcomas (STS). The addition of intraoperative radiation therapy (IORT) can deliver high dose radiation boost to anticipated “high risk” margins while sparing adjacent structures. Methods: A retrospective review (2004-2012) was performed of STS treated with surgical resection and IORT using HDR brachytherapy for anticipated close/positive margins. Results: Twenty-four patients underwent 25 resections with IORT (1 patient had 2 separate recurrences). Tumors were primary in 72%, deep in 96% and intermediate/high grade in 84%. Tumor locations were extremity (44%), retroperitoneal (40%), truncal (12%) and neck (4%). Common histologies included pleomorphic (32%), liposarcoma (12%) and myxofibrosarcoma (12%). Neoadjuvantly, 3 received chemotherapy and 13 received EBRT (median 50Gy; range 45-54). Median IORT dose was 12Gy (range 10-17.5). Margins were microscopically positive in 20%; none were grossly positive. Adjuvantly, 5 received EBRT (median 46Gy, range 45-50) and 2 received chemotherapy. Median follow-up was 20.1 months (range 2.7-96.4). No recurrences occurred at the IORT sites. Two-year LR free survival was 60.8% and disease specific survival was 84%. Conclusion: Use of IORT at time of STS resection was effective at preventing LR at the treated site despite “high risk” features.

Modern Gamma Knife radiosurgery of vestibular schwannomas: treatment concept, volumetric tumor response, and functional results.

The objective of the present study was longitudinal evaluation of the volumetric tumor response and functional results after Gamma Knife radiosurgery of vestibular schwannomas, performed according to the modern standards of treatment. From October 2003 to September 2007, 133 consecutive patients with vestibular schwannomas were treated according to the concept of robotic Gamma Knife microradiosurgery, which is based on precise irradiation of the lesion, sparing adjacent structures, and delivery of the high radiation energy to the target. Multiple small-sized isocenters located within the border of the neoplasm were applied. The mean marginal dose was 11.5 Gy (range, 11-12 Gy). In total, 126 cases with a minimum posttreatment follow-up of 2 years (range, 2-7 years; median, 4 years) were analyzed. Temporary enlargement was noted in 25% of tumors at 6 months after radiosurgery. At 3 years of follow-up, tumor shrinkage, stabilization, and increase in volume were marked in 73%, 23%, and 4% of cases, respectively. All progressing lesions spontaneously stabilized later on and did not require additional management. In 3% of patients, transitory impairment of the facial nerve function was marked; however, neither its permanent dysfunction nor trigeminal neuropathy attributed to radiosurgery was noted. Impairment of hearing compared to its pretreatment level was revealed in 4%, 12%, 13%, and 16% of patients at 6 months, 1 year, 2 years, and 3 years after radiosurgery, respectively, and this trend was statistically significant (P = 0.0042). Overall, 77% of patients with serviceable hearing before treatment preserved it 3 years thereafter. In conclusion, modern Gamma Knife radiosurgery provides effective and safe management of vestibular schwannomas. Nevertheless, possible temporary tumor enlargement, delay of its growth arrest, transient dysfunction of the cranial nerves, and gradual deterioration of hearing after irradiation should be always taken into consideration.