2.1 Study design

This systematic review and meta-analysis was conducted to evaluate the outcomes of sacrectomy and post-sacrectomy reconstruction specifically for malignant sacral tumors. The study adhered to PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines to ensure comprehensive and transparent reporting.⁵

2.2 Endpoints

The primary study endpoints include reoperation, infections, systemic complications, and hardware failure rates after sacrectomy and reconsutrction. Hardware failure was further classified into screw loosening, pullout, fracture; rob fracture; connector failure; plate failure; suboptimal screw placement; rod deformation; aspetic loosening; septic loosening; and hardware migration. Infections were further classified into superficial and deep surgical site infections.

2.3 Eligibility criteria

Inclusion Criteria: Studies must report outcomes following partial or total sacrectomy specifically for malignant sacral tumors or malignancies and include patient data with a minimum follow-up period of 30 days. At least one of the following outcome measures must be reported: resurgery rate (30 days or 1 year), infection rate (30 days or 1 year), systemic complications (30 days or 1 year), or mechanical complications. The studies should involve patients undergoing either partial or total sacrectomy and be published in peer-reviewed journals in English or with English translations. Additionally, studies must provide sufficient detail on the demographic and clinical characteristics of the patient population and report follow-up data at multiple time points (30 days and 1 year) if available.

Exclusion Criteria: Case reports, letters to the editor, and editorials without original data will be excluded, as will studies with a follow-up period of less than 30 days. Studies lacking all required outcome measures or focusing on non-malignant conditions or conditions unrelated to sacral tumors or malignancies will also be excluded.

2.4 Information sources

A comprehensive search was conducted using electronic databases including PubMed from inception to July 2025. References of relevant studies and review articles were manually checked for additional studies.

2.5 Search strategy

A comprehensive search was conducted in PubMed using the following queries to identify relevant studies for the systematic review.•Search Query: "sacrum reconstruction"•Search Query: "sacrum resection"•Search Query: "(sacrum) AND (surgery)"•Search Query: "sacrectomy"

These queries were designed to capture a wide range of studies related to sacral surgery, including both reconstruction and resection procedures. The search results were screened for relevance based on the inclusion criteria.

2.6 Study selection

One reviewer screened titles and abstracts of identified studies for eligibility. Full-text articles were reviewed for final inclusion based on the criteria. Discrepancies were resolved through discussion and consensus with a third reviewer.

2.7 Data extraction

Data were extracted independently by two reviewers using a standardized form. Extracted data included study characteristics (e.g., author, year, sample size), patient demographics, type of sacrectomy, outcome measures (resurgery rates, infection rates, systemic complications, mechanical complications), and follow-up duration.

2.8 Risk of bias assessment

The quality of the included studies was assessed using the STROBE standardized criteria to ensure the reliability and validity of the findings.⁶

2.9 Data synthesis and statistical analysis

Data synthesis was conducted using JAMOVI software. MAJOR module was used to synthesize outcome of resurgery rates, infection rates, systemic complications, and mechanical complications between studies. The I² statistic was employed to evaluate the heterogeneity of the included studies. This approach enabled a comprehensive analysis of the outcomes associated with sacrectomy and post-surgical reconstruction.⁷

2.10 Ethics and dissemination

This study did not directly involve human subjects or animal experiments; therefore, ethical approval was not required. The findings of this systematic review and meta-analysis will be disseminated through peer-reviewed publications and presentations at relevant conferences.

3.1 Literature search and study characteristics

A comprehensive literature search was conducted in the PubMed database in accordance with PRISMA 2020 guidelines, yielding a total of 11,553 records. After the removal of 9070 records deemed irrelevant to oncologic sacral surgery based on titles and keywords, 2483 abstracts were screened. Of these, 2415 were excluded due to non-compliance with the predefined inclusion criteria, such as non-oncologic indications, case reports, technical notes, or studies with fewer than 10 patients. A total of 68 full-text articles were assessed for eligibility, resulting in the exclusion of 40 studies. Ultimately, 28 retrospective cohort studies published between 2000 and 2025 were included in the final qualitative synthesis and quantitative meta-analysis, encompassing 1176 patients who underwent sacrectomy or hemisacrectomy for primary or metastatic sacral tumors.^8–34,39 The literature search was completed in July 2025, ensuring the inclusion of the most up-to-date evidence. The included studies demonstrated variation in surgical approaches (posterior-only versus combined anterior–posterior), reconstruction techniques (e.g., spinopelvic fixation, soft tissue flaps), and follow-up durations, allowing for a comprehensive evaluation of perioperative complications and clinical outcomes following oncologic sacrectomy (see Table 1) (see Fig. 1).

Close

Fig. 1 PRISMA flowchart.

Export to PPT

3.2 The pooled outcome rates

The pooled outcome rates reveal that the reoperation rate due to mechanical and anatomical reasons is 8.0 % within 30 days, with 50 out of 613 cases requiring reoperation. This rate increases to 15.0 % by the 12-month mark, with 81 reoperations out of 535 cases. Infection rates are notably high, with a 24.2 % incidence within 30 days (195 infections out of 807 cases), rising to 30.6 % at 12 months (108 infections out of 353 cases). Systemic complications occur in 20.6 % of cases within the first 30 days, affecting 91 out of 440 patients. Additionally, mechanical and anatomical failures are observed in 10.8 % of cases within 30 days, with 75 failures out of 691 cases (Table 2).

3.3 The data synthesis results

The synthesized data for reoperation rates shows a 30-day rate of 5.8 %, with moderate heterogeneity indicated by an I² of 60 %, reflecting some variability in rates across studies. By the 12-month mark, the reoperation rate increases to 14.0 %, accompanied by a moderate level of heterogeneity (I² of 75 %). For infections, the 30-day rate is 26.6 %, with high heterogeneity (I² of 87 %), indicating substantial variability across studies. This rate rises to 32.2 % at 12 months, with even higher heterogeneity (I² of 90 %). Systemic complications present a synthesized 30-day rate of 20.0 %, with moderate heterogeneity (I² of 69 %), suggesting some variability but more consistency compared to infection rates. Mechanical and anatomical failures have a synthesized 30-day rate of 8.1 %, with high heterogeneity (I² of 71.5 %), highlighting considerable variability in reported rates among studies (Table 3see Table. 4).

3.4 Subgroup comparison: total sacrectomy versus subtotal sacrectomy

Several retrospective cohort studies have investigated the impact of total versus partial sacrectomy on patient outcomes. Feghali et al. (2021), analyzing 57 patients (45 partial, 12 total), reported that total sacrectomy does not independently increase the risk of complications. Similarly, Maricevich et al. (2014), in a cohort of 54 patients (38 partial, 16 total), found no significant difference in complication rates attributable to the extent of sacrectomy. However, Houdek et al. (2020), studying a larger sample of 196 patients (176 partial, 20 total), observed that while total sacrectomy and subtotal sacrectomy had comparable infection rates, total sacrectomy was associated with significantly worse functional outcomes and reduced ambulatory capacity.

3.5 Subgroup comparison: impact of surgical approach on complication and functional outcomes

Across the included studies, the surgical approach—whether anterior-only, posterior-only, or combined—did not significantly affect the rates of surgical site infections (SSI) or intraabdominal complications. Both Maricevich (2014) and Marmouset (2022) found no association between approach and flap-related or intraabdominal complication rates. Similarly, Feghali (2021) and Milne (2014) emphasized that other factors, such as instrumentation, tumor volume, and vascular involvement, were more predictive of postoperative complications than the surgical approach itself.

3.6 Subgroup comparison: effect of sacrectomy level on neurological and functional outcomes

Sacrectomy level showed a consistent and clinically meaningful impact on neurological and functional outcomes. Houdek (2020) demonstrated that patients undergoing low sacrectomies (below S2) were significantly more likely to ambulate independently than those undergoing high sacrectomies (above S2) (65 % vs. 35 %, p < 0.001). This finding aligns with Clarke (2012) and Kanay (2025), both of whom reported higher rates of neurological complications with proximal resections. Although Milne (2013, 2014) found no difference in overall perioperative complication rates between high and low resections, the functional consequences, particularly regarding mobility and continence, appear to be more profound in high-level resections. Feghali (2021) further supports this by identifying bilateral proximal nerve root sacrifice as an independent risk factor for complications. Overall, sacrectomy level, particularly the involvement of S1 and S2 nerve roots, appears to be a stronger predictor of long-term neurological deficits than surgical approach.

3.7 Quality and bias assessment

Table 2 presents the quality assessment of various studies included in the analysis, evaluating key aspects such as setting, participants, variables, data sources, and statistical methods. The studies were assessed on the quality of descriptive and outcome data, as well as their main results and limitations. Several studies, such as those by Weidlich, Houdek, Khaled, Milne, Maricevich, and Melton, were consistently rated as "well" across most categories. However, other studies, like those by Paul, Beppu, and Marmouset, received "partly" ratings for setting and participant-related variables, with limitations in outcome data. Despite these variations, all studies were included in the final analysis.

4.1 Importance of the study and narrative scope

The importance of this topic lies in the anatomic uniqueness of the sacrum and its integration with the mobile spine, which presents significant surgical challenges. The sacral region is frequently affected by metastases and less commonly by primary tumors. In cases where surgery is indicated, it is well-established that R0 resections, which achieve negative margins, significantly improve survival rates.³ Even R1 resections, which leave microscopic residual disease, have been shown to confer better outcomes than R2 resections, where gross tumor remains. This underscores the critical role of surgical intervention in managing sacral tumors.^3,4

However, sacral surgeries are associated with a high rate of complications due to the complexity of the anatomic region and the elevated risk of infection following resection^2–4,8–39. This study systematically evaluates these complications, categorizing them into four primary groups: reoperation due to mechanical or anatomic reasons, infection, systemic complications, and mechanical or anatomic failure. Complications were examined across two key periods: within 30 days post-surgery and at 1-year follow-up.

The significance of this study lies in its comprehensive evaluation of all available evidence on this topic, providing both pooled and synthesized results. By offering an analysis of surgical outcomes and complications, this study contributes valuable insights for improving patient care and guiding future surgical approaches in the management of sacral tumors.

4.2 Sacrectomy complications in the current evidence

4.3 Lessons from subgroup analyzes

Our subgroup analyses reveal that while total sacrectomy is not independently associated with increased postoperative complications compared to subtotal sacrectomy, it is clearly linked to poorer functional outcomes. Both Feghali et al. and Maricevich et al. found no significant difference in infection or reoperation rates between total and partial resections. However, Houdek et al. demonstrated that total sacrectomy significantly compromises ambulatory capacity and functional scores, underscoring the greater neurological burden associated with more extensive resection.

Among the factors assessed, sacrectomy level emerged as the most critical determinant of postoperative neurological and functional outcomes. High sacral resections involving the S1–S2 nerve roots were consistently associated with increased rates of motor deficits, incontinence, and impaired mobility, as supported by the findings of Houdek, Clarke, and Kanay. In contrast, the surgical approach—whether anterior-only, posterior-only, or combined—did not show a consistent association with complication rates across studies. This suggests that while the technical route of access may affect intraoperative complexity, the extent and level of nerve root sacrifice more directly influence long-term patient function. These findings highlight the importance of sacral nerve preservation in surgical planning and patient counseling.

4.4 Quality of the current evidence

The quality of the current evidence regarding sacrectomy and post-sacrectomy reconstruction is variable but overall reflects significant heterogeneity in study designs, patient populations, and outcome reporting. Most of the studies included in this review are retrospective cohort studies, which are inherently limited by their observational nature and susceptibility to biases such as selection and reporting biases. Although many studies adhere to recognized standards, such as the STROBE criteria, the variability in reporting outcome measures, particularly regarding the definitions of complications and follow-up durations, presents challenges in synthesizing data across studies.

Heterogeneity, as reflected by high I² statistics in areas such as infection rates (I² = 87 %) and mechanical failures (I² = 71.5 %), indicates that significant differences exist between studies. There are many reasons for this heterogeneity, including the nerves sacrificed during surgery, the unique nature of various cancers, the wide range in patient demographics, the experience of surgeons, and the infrastructure of the clinics.

Some studies, such as those by Weidlich, Houdek, and Milne, were of relatively high quality, offering detailed descriptive and outcome data with robust statistical analysis. However, other studies, particularly those with smaller sample sizes or studies with great sample heterogenity issues, exhibited limitations in both the depth and consistency of their findings.

Despite these limitations, the overall body of evidence provides valuable insights into the outcomes and complications associated with sacrectomy. The consistency of findings related to high infection and reoperation rates across multiple studies reinforces the reliability of these observations, even in the presence of heterogeneity. Future research should focus on improving the methodological rigor of studies in this area, including prospective designs, standardized outcome reporting, and longer-term follow-up to better capture the full spectrum of complications and patient outcomes following sacral surgery.

4.5 Future perspective and what lessons learned

As we advance in the field of sacral tumor management, several key areas warrant focused attention to enhance patient outcomes and surgical efficacy. Teamwork stands out as a cornerstone of future progress, emphasizing the need for multidisciplinary collaboration among surgeons, oncologists, radiologists, and rehabilitation specialists. A cohesive team approach ensures comprehensive care, integrating diverse expertise to address the complex challenges of sacral surgeries effectively.

Given the risky nature of sacral procedures, it is imperative to refer candidate patients to advanced hospitals with robust infrastructure and specialized experience. These centers are better equipped to manage the intricacies of sacral resections and associated complications, thereby improving patient safety and outcomes. Advanced hospitals offer access to cutting-edge technology and experienced personnel, which are crucial for handling the complexities of sacral tumor resections.

Patient-based decision-making should remain central to surgical planning, taking into account individual patient factors such as overall health, tumor characteristics, and personal preferences. Tailoring treatment plans to the specific needs of each patient ensures that the chosen approach aligns with their unique circumstances, optimizing both safety and effectiveness.

Lastly, the indispensability of sacral resections for effective tumor management cannot be overstated. Despite the associated risks, these procedures are often critical for achieving negative margins and improving survival rates. Future research should continue to refine surgical techniques and protocols, aiming to mitigate risks and enhance the benefits of sacral resections. By focusing on these areas, we can advance the field and improve outcomes for patients undergoing this challenging yet essential treatment.