(P 362) A NEW ROCK BAND FOR DIAPHRAGMATIC RECONSTRUCTION IN LEFT RETROPERITONEAL SARCOMA SURGERY

Objective: In the surgical management of left-sided retroperitoneal sarcomas (RPS), complete resection often requires removing adjacent structures, including the diaphragm, to achieve clear margins. This study evaluates the efficacy and safety of a novel diaphragmatic reconstruction technique for cases requiring resection of the postero-medial part of the diaphragm along with the left pillar.

Methods: We conducted a retrospective analysis of consecutive patients who underwent surgery for left retroperitoneal liposarcoma (RP-LPS) at the Sarcoma Surgery Unit, IRCCS-Humanitas Research Hospital, from January 2023 to December 2023, where diaphragmatic resection was necessary and reconstruction was performed using our proposed technique. The ROCK (Robust Organic Composite for Kinetic restoration of the diaphragm) band is a rectangular polytetrafluoroethylene (PTFE) band (Figure 1), measuring 10 cm by 2.5 cm, folded in two layers and fixed with non-absorbable sutures. Figure 2 shows a schematic representation of the surgical technique. The lower extremity of the band is anchored to the pre-vertebral fascia, and the upper extremity is secured to the diaphragm near the aortic hiatus. Care is taken to avoid constricting the aorta during fixation. The cut border of the diaphragm is then attached to the lateral/external layer of the band with continuous running sutures. An intercostal drainage tube is placed, and an air bubble test is performed to ensure the repair's effectiveness.

Results: Four patients were treated using the ROCK band technique. Figure 3 presents the pre-operative CT scan of these patients. Table 1 shows patient’ characteristics, treatment details, and short-term postoperative outcomes. The median age was 56.5 years (IQR 52.5-61.75), with a male/female ratio of 1/3. The median tumor size was 24.5 cm (IQR 11.0-37.2). The median resected organ score was 4 (IQR 2-6). No cases of tumor rupture or R2 resections were recorded. The median operative time was 409.5 minutes (IQR 362.5-468.0), and the median intraoperative blood loss was 400 cc (IQR 237.5-625.0). Intraoperative blood transfusions were required in 2 cases (50.0%). No complications related to the ROCK band were documented, including no post-operative diaphragmatic hernia or respiratory failure. The median postoperative day for chest tube removal was the 8th (IQR 6.5-9). The median length of stay (LOS) was 14.5 days (IQR 10.3–18.3). For patients 1 and 2, the hospital stay was prolonged due to their distant domicile from the hospital, ensuring extended observation to exclude short-term complications. Microscopic invasion of the diaphragm was found in all cases.

Conclusion: The ROCK band technique offers significant benefits for diaphragmatic reconstruction in left RP-LPS surgery, restoring anatomical structure and allowing tension-free closure. This method enhances both mechanical strength and biological compatibility for effective diaphragm repair. Our findings suggest this approach is safe and effective, with no observed complications. This technique could be adapted for other surgical scenarios involving resection of the postero-medial part of the left diaphragm and left pillar. Future studies with larger cohorts are needed to validate these findings and refine the technique.