Abstract
BACKGROUND: En bloc resection of the sacrum, whether in the form of total or partial sacrectomy, is the mainstay treatment for patients with primary malignant sacral tumors. However, these surgical procedures can lead to pelvic floor dysfunction, with symptoms such as incontinence and impaired rectal function that can severely impact patients' quality of life. Therefore, effective interventions to restore pelvic floor function would be helpful for affected patients. Synthetic mesh has been well established for abdominal soft tissue repair and in enhancing pelvic floor muscle tension in patients with pelvic organ prolapse; however, its role in sacrectomy has not been well documented. QUESTIONS/PURPOSES: Did patients treated with synthetic mesh reconstruction after sacrectomy for primary malignant sacral tumors (1) achieve better scores for quality of life, (2) achieve better scores for pelvic floor symptom and function, (3) develop improved EMG measures of pelvic floor muscle activity, and (4) experience more complications than patients treated without mesh? METHODS: Between April 2011 to June 2021, a total of 90 patients diagnosed with primary sacral tumor and who underwent surgery in our institution were retrospectively evaluated. For this study, inclusion criteria were patients with primary malignant sacral tumors undergoing en bloc resection for long-term tumor control or cure. Exclusion criteria for this study were patients who underwent total sacrectomy or high-level sacrectomy with bilateral S2 nerve resection. A total of 26 patients were included for analysis. Our study aimed to compare patients treated with synthetic mesh with those treated without mesh as part of pelvic floor reconstruction. Prior to 2017, mesh was not used in reconstruction after sacrectomy. After 2017, it has been progressively incorporated into the standard surgical approach, except in patients with chronic infection, severe pelvic adhesion, financial constraints, or patients who declined. All patients included had at least 2 years of follow-up, with a median of 37 months in the mesh group and 54 months in the no-mesh group. The baseline characteristics of two groups did not differ in important ways, with a mean ± SD age of 63 ± 13 years in the mesh group and 64 ± 14 years in the no-mesh group. There were 9 (of 10) men in the mesh group and 10 (of 16) men in the no-mesh group. The median (IQR) tumor volume was 118 cm3 (90) and 66 cm3 (140) in the mesh and no-mesh groups, respectively. Nerve roots were predominantly preserved at the S3. We used the 36-Item Short Form Survey (SF-36) to assess quality of life. Pelvic floor dysfunction was evaluated using the Pelvic Floor Impact Questionnaire-7 (PFIQ-7). It includes three scales: the Urinary Impact Questionnaire (UIQ-7), the Colorectal-anal Impact Questionnaire (CRAIQ-7), and the Pelvic Organ Prolapse Impact Questionnaire (each range 0 to 100). The summary scores are calculated by adding up the scale scores (range 0 to 300), with lower scores indicating better function. Pelvic floor muscle strength was objectively evaluated using surface EMG. An independent t-test or Mann-Whitney U test was used to compare the continuous variables depending on whether normal distribution was met. Categorical variables were analyzed using the chi-square test or Fisher exact test. RESULTS: Patients who underwent synthetic mesh reconstruction had higher mean ± SD scores by a clinically important margin for physical functioning (59 ± 9 versus 47 ± 11, p = 0.02; minimum clinically important difference [MCID] 5.4), general health (60 ± 7 versus 50 ± 9, p = 0.03; MCID 6.8), vitality (56 ± 13 versus 44 ± 9, p = 0.01; MCID 9.1), and physical component summary (56 ± 9 versus 46 ± 10, p = 0.04; MCID 5) compared with the patients in the no-mesh group, respectively. For PFIQ-7 scores, we found no clinically important difference in UIQ-7 (13 ± 5 versus 20 ± 9, p = 0.02; MCID 11.5) or the summary score (43 ± 20 versus 65 ± 28, p = 0.03; MCID 36) between groups. However, patients who underwent mesh reconstruction had lower scores for the CRAIQ-7 (20 ± 13 versus 35 ± 18, p = 0.03; MCID 8) than patients without mesh reconstruction. The surface EMG measurement exhibited higher quick flick activity in the mesh group (75 ± 10 µV versus 56 ± 20 µV, p = 0.01) compared with the no-mesh group. Our study was too small for a meaningful statistical comparison of complications; however, there did not appear to be substantial between-group differences in terms of complications. In the mesh group, 2 (of 10) patients developed superficial infection, while in the no-mesh group, superficial infection (3 of 16), deep infection (1 of 16), rectocele (1 of 16), and hematoma (1 of 16) were observed. CONCLUSION: Pelvic floor reconstruction using synthetic mesh after sacrectomy was associated with improved quality of life and pelvic floor function in patients with primary malignant sacral tumors. Specifically, synthetic mesh use is associated with improved physical quality of life, reduced pelvic symptom burden, and enhanced muscle strength. These findings support its role as a potential approach for pelvic floor reconstruction after sacrectomy. However, studies with larger sample sizes are needed to validate our findings and to further explore potential differences across patient subgroups, including different genders and levels of nerve preservation. LEVEL OF EVIDENCE: Level III, therapeutic study.