Lumbopelvic shortening and local host bone-to-host bone reconstruction: a surgical method for lumbopelvic fusion following total sacrectomy.

PURPOSE: Primary sacral tumors are rare, representing fewer than 7% of spinal neoplasms. Following total sacrectomy, lumbopelvic instrumentation and fusion carries a high risk of non-union with no current consensus on fixation techniques to augment bony defects. We aim to describe the outcome of a reconstruction technique following total sacrectomy whereby lumbopelvic shortening is performed and the posterior pelvic ring is compressed to enable contact with the native L5 vertebra. METHODS: Retrospective chart review of 2 patients with 2 and 7 years post-operative follow-up. A review of hospital records including clinical assessments, complications, pathology and imaging reports. RESULTS: Patient 1 was a 17-years-old male with recurrent sacral chondrosarcoma, who presented with lumbosacral neuropathic pain and radiculopathy after failed intralesional surgery. Patient 2 was a 51-years-old male with chronic low back pain caused by a large low-grade chondroid sacral chordoma. Reconstruction technique involved mobilizing the L5 vertebra into the pelvis and pelvic ring closure to obtain host-bone-to-bone contact, eliminating the need for alternative grafts. Post-operative complications included superficial abdominal wound drainage, lower limb DVT, pulmonary emboli and deep pelvic infection. Serial CT scans demonstrated bony fusion in both patients. Neither patients had evidence of tumor recurrence and were able to ambulate at recent follow-up. Imaging demonstrated changed acetabular version of - 4.6/- 8.1 and - 14.4/- 14.8 (patient 1/2, R/L, respectively). CONCLUSION: Primary lumbopelvic shortening represents an alternative local autograft reconstructive technique for management of large sacral defects following total sacrectomy. This technique obviates the additional morbidity and surgical cost associated with the use of previously described techniques.

Expression of far upstream element-binding protein 1 correlates with c-Myc expression in sacral chordomas and is associated with tumor progression and poor prognosis.

The far upstream element (FUSE)-binding protein 1 (FUBP1), a well-known transcriptional regulator of the proto-oncogene c-Myc, has been demonstrated by previous work to be aberrantly expressed in a variety of tumors and plays a critical role in tumor progression; however, its expression and function in relatively rare and aggressive chordomas remains unclear. In this retrospective study, we reviewed clinicopathologic characteristics of 40 patients diagnosed with sacral chordoma, and analyzed 40 tumor and 20 distant normal tissues obtained from patients during the primary surgical tumor excision. Using immunohistochemistry, we observed an up-regulation in the expression of FUBP1 and c-Myc in sacral chordomas compared with the normal tissues (P = 0.001 for both). Additionally, positive correlations of FUBP1 expression with c-Myc (γ = 0.651, P < 0.001) and the cell proliferation index Ki-67 expression (γ = 0.447, P = 0.004) were indicated using Spearman's rank correlation coefficient. Increased expression of FUBP1 was significantly associated with tumor invasion into the surrounding muscles (P = 0.002). Kaplan-Meier curves demonstrated the association between FUBP1 levels and the patients' local recurrence-free survival (LRFS) (P < 0.001) but not with the overall survival (OS) (P = 0.070). The independent prognostic significance of FUBP1 levels for the LRFS was indicated by multivariate analysis (HR = 4.272; 95% CI, 1.133-16.112; P = 0.032). Our findings demonstrate an association between FUBP1 levels and chordoma progression and prognosis, suggesting that FUBP1 can be used as a biomarker and a potential therapeutic target.

Balancing benefits and limitations of linear energy transfer optimization in carbon ion radiotherapy for large sacral chordomas.

Background and Purpose: A low linear energy transfer (LET) in the target can reduce the effectiveness of carbon ion radiotherapy (CIRT). This study aimed at exploring benefits and limitations of LET optimization for large sacral chordomas (SC) undergoing CIRT. Materials and Methods: Seventeen cases were used to tune LET-based optimization, and seven to independently test interfraction plan robustness. For each patient, a reference plan was optimized on biologically-weighted dose cost functions. For the first group, 7 LET-optimized plans were obtained by increasing the gross tumor volume (GTV) minimum LETd (minLETd) in the range 37-55 keV/µm, in steps of 3 keV/µm. The optimal LET-optimized plan (LETOPT) was the one maximizing LETd, while adhering to clinical acceptability criteria. Reference and LETOPT plans were compared through dose and LETd metrics (D x , L x to x% volume) for the GTV, clinical target volume (CTV), and organs at risk (OARs). The 7 held-out cases were optimized setting minLETd to the average GTV L98% of the investigation cohort. Both reference and LETOPT plans were recalculated on re-evaluation CTs and compared. Results: GTV L98% increased from (31.8 ± 2.5)keV/µm to (47.6 ± 3.1)keV/µm on the LETOPT plans, while the fraction of GTV receiving over 50 keV/µm increased on average by 36% (p < 0.001), without affecting target coverage goals, or impacting LETd and dose to OARs. The interfraction analysis showed no significant worsening with minLETd set to 48 keV/µm. Conclusion: LETd optimization for large SC could boost the LETd in the GTV without significantly compromising plan quality, potentially improving the therapeutic effects of CIRT for large radioresistant tumors.

A Bibliometric Analysis of the 20 Most Cited Articles on Sacrococcygeal Chordomas.

This study aims to summarize sacrococcygeal chordoma literature through bibliometric analysis and to offer insights into key studies to guide clinical practices and future research. The Web of Science database was searched using the terms "sacral chordoma", "chordomas of the sacrum", "chordomas of the sacral spine", "chordomas of the sacrococcygeal region", "coccygeal chordoma", and "coccyx chordoma". Articles were analyzed for citation count, authorship, publication date, journal, research area tags, impact factor, and evidence level. The median number of citations was 75 (range: 53-306). The primary publication venue was the International Journal of Radiation Oncology, Biology, Physics. Most works, published between 1999 and 2019, featured a median journal impact factor of 3.8 (range: 2.1-7) and predominantly fell under the research area tag, radiation, nuclear medicine, and imaging. Of these articles, 19 provided clinical data with predominantly level III evidence, and one was a literature review. This review highlights the increasing volume of sacrococcygeal chordoma publications over the past two decades, indicating evolving treatment methods and interdisciplinary patient care. Advances in radiation, particularly intensity-modulated radiation therapy (IMRT) and proton beam therapy, are believed to be propelling research growth, and the lack of level I evidence underscores the need for more rigorous studies to refine treatment protocols for sacrococcygeal chordomas.

Chondromyxoid fibroma of the sacrum: A case report and literature review.

BACKGROUND: Chondromyxoid fibroma (CMF) is an extremely rare, benign cartilaginous tumor that makes up <0.5% of all bone tumors, typically presenting in the second or third decade of life. CMF of the sacrum is exceedingly rare, with only seven documented cases reported in the neurosurgical literature. CASE DESCRIPTION: We report a case of a 35-year-old female with a 3 month history of lower back pain after sustaining a fall on her sacrum/coccyx presenting with a progressive complaint of localized lower back pain, occasional urinary retention without incontinence, gluteal hypesthesia, and pressure below the gluteal crease. Imaging demonstrated a large, expansile enhancing soft-tissue lesion involving the sacrum, distal to the S2-3 disc space. The tumor was removed with partial sacrectomy for open en bloc resection with partial nerve sparing. The patient was found at 1.5-year follow-up with the improvement of symptoms, no recurrence, and no residual neurologic dysfunction. CONCLUSION: Sacral CMF is a rare clinical entity that may mirror more aggressive sacral pathology, including chordoma, in both clinical presentation and imaging characteristics. A review of the available literature regarding diagnosis, surgical management options, and prognosis for sacral CMF is provided.