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Pelvic tumor resection with sacrectomy for locally recurrent rectal cancer is a challenging operation with a high complication rate and poor prognosis. We report a case of pelvic tumor resection with sacrectomy by transperineal endoscopy following laparoscopic dissection for locally recurrent rectal cancer. A 70-year-old man underwent laparoscopic abdominoperineal resection for rectal cancer and was diagnosed with local pelvic recurrence on follow-up computed tomography (CT) three years postoperatively. As the recurrence was in contact with the front of the sacrum, we concluded that distal sacrectomy was necessary to ensure a surgical margin. We safely performed combined laparoscopic and transperineal endoscopic pelvic tumor resection with sacrectomy by exposing the surface of the sacrum from both abdominal and transperineal approach. The operative time was 200 minutes, with minimal blood loss. There was no tumor exposure on the surgically dissected surface, and the patient was discharged without complications 14 days postoperatively. Transperineal endoscopy may be useful for pelvic tumor resection with sacrectomy for locally recurrent rectal cancer.

Surgical interventions for musculoskeletal tumor resection are particularly challenging in the pelvic region due to their anatomical complexity and proximity to vital structures. Several techniques, such as surgical navigation or patient-specific instruments (PSIs), have been introduced to ensure accurate resection margins. However, their inclusion usually modifies the surgical approach making it more invasive. In this study, we propose to combine both techniques to reduce this invasiveness while improving the precision of the intervention. PSIs are used for image-to-patient registration and the installation of the navigation’s reference frame. We tested and validated the proposed setup in a realistic surgical scenario with six cadavers (12 hemipelvis). The data collected during the experiment allowed us to study different resection scenarios, identifying the patient-specific instrument configurations that optimize navigation accuracy. The mean values obtained for maximum osteotomy deviation or MOD (maximum distance between the planned and actual osteotomy for each simulated scenario) were as follows: for ilium resections, 5.9 mm in the iliac crest and 1.65 mm in the supra-acetabular region, and for acetabulum resections, 3.44 mm, 1.88 mm, and 1.97 mm in the supra-acetabular, ischial and pubic regions, respectively. Additionally, those cases with image-to-patient registration error below 2 mm ensured MODs of 2 mm or lower. Our results show how combining several PSIs leads to low navigation errors and high precision while providing a less invasive surgical approach.

Abstract Background Local treatment in pelvic Ewing sarcoma (ES) consists of operation, radiation therapy, or a combination of both. Reported outcomes vary depending on the treatment modality performed. It is the objective of this study to analyze surgical outcome and complications as well as oncological outcome and complications of chemo- and radiation therapy in this patient cohort and evaluate prognostic factors. Methods Retrospective review of 104 patients who underwent tumor resection for pelvic ES from 1988 to 2014. Results All patients underwent pelvic resection and radiation therapy was administered in 77.9%. Margins were clear in 94.2%. The response to chemotherapy was good in 78.8%. Local recurrence occurred in 7.7%. The presence of distant metastases at the time of operation was the most important negative predictor for overall survival (p = 0.003). The cumulative 5- and 10-year survival rates were 82.7% and 80.1% for non-metastasized and 61.4% and 41.6% for metastasized pelvic ES at operation. In the presence of a single-distant metastatic site at operation compared to multiple metastatic sites, the cumulative survival rates were 64.3% versus 50% at five and 50.7% versus 16.7% at 10 years. Conclusions A combined treatment approach of tumor resection and radiation therapy leads to a local control and overall survival rates comparable with those of extremity locations in this study’s patient cohort with localized pelvic ES. Therefore, surgical tumor resection (combined with (neo-)adjuvant radiation therapy) in non-metastatic pelvic ES seems feasible. In metastatic patients, however, the significance of tumor resection as a part of local treatment remains less certain and improved outcomes of combined local treatment approaches need to be weighed against these patients’ prognosis and quality of life.

Patient-specific instruments (PSIs) have become a valuable tool for osteotomy guidance in complex surgical scenarios such as pelvic tumor resection. They provide similar accuracy to surgical navigation systems but are generally more convenient and faster. However, their correct placement can become challenging in some anatomical regions, and it cannot be verified objectively during the intervention. Incorrect installations can result in high deviations from the planned osteotomy, increasing the risk of positive resection margins. In this work, we propose to use augmented reality (AR) to guide and verify PSIs placement. We designed an experiment to assess the accuracy provided by the system using a smartphone and the HoloLens 2 and compared the results with the conventional freehand method. The results showed significant differences, where AR guidance prevented high osteotomy deviations, reducing maximal deviation of 54.03 mm for freehand placements to less than 5 mm with AR guidance. The experiment was performed in two versions of a plastic three-dimensional (3D) printed phantom, one including a silicone layer to simulate tissue, providing more realism. We also studied how differences in shape and location of PSIs affect their accuracy, concluding that those with smaller sizes and a homogeneous target surface are more prone to errors. Our study presents promising results that prove AR’s potential to overcome the present limitations of PSIs conveniently and effectively.