Surgical techniques for spinopelvic reconstruction following total sacrectomy: a systematic review. Eur Spine J. 2014;23:305-319. [PMID: 24150036 DOI: 10.1007/s00586-013-3075-z]

Notochordal cell derived lesions: a 55-year casuistic analysis of 50 cases with radiologic-pathologic correlation in a tertiary referral hospital, and literature review

Distinct lesions are derived from notochordal cells (NCDL), ranging from benign to malignant ones. This study presents fifty NCDL cases diagnosed in a tertiary hospital of reference from the past 55 years: forty-two conventional chordomas, including one chondroid chordoma subtype, four benign notochordal cell tumors (BNCT), two conventional chordomas with BNCT foci, and two dedifferentiated chordomas. All patients were adults. Three BNCT were incidentally diagnosed, and one case presented local pain. Chordomas began with local pain and/or neurological symptoms. BNCT were well-defined intraosseous lesions, hypointense on T1-weighted images (WI) and hyperintense on T2-WI, without enhancement in the contrast. Conventional chordomas, including its chondroid subtype, were lobulated masses with cortical disruption and soft tissue extension, hypointense on T1-WI and hyperintense on T2-WI, with variable contrast enhancement. BNCT were histologically composed of solid sheets of vacuolated cells with clear cytoplasm and round and central nuclei. No atypia, lobular growth pattern, myxoid matrix, or bone infiltration were seen. Conventional chordomas were histologically composed of physaliphorous cells in a myxoid stroma with lobulated and infiltrating growth patterns. Observational follow-up using radiological controls was decided on for the BNCT cases. None of these cases presented local recurrence or metastasis. En-bloc resection and adjuvant radiotherapy were selected for sacral and vertebral chordoma cases. Sixteen patients died due to tumor-related factors; twenty-eight presented local recurrence, and four developed distant metastases. New therapeutic options are being studied for chordoma cases. Clinical, radiological, and histopathological data are necessary to properly diagnose and follow up of NCDL.

Surgical and Oncologic Outcome following Sacrectomy for Primary Malignant Bone Tumors and Locally Recurrent Rectal Cancer

INTRODUCTION

Bone sarcoma or direct pelvic carcinoma invasion of the sacrum represent indications for partial or total sacrectomy. The aim was to describe the oncosurgical management and complication profile and to analyze our own outcome results following sacrectomy.

METHODS

In a retrospective analysis, 27 patients (n = 8/10/9 sarcoma/chordoma/locally recurrent rectal cancer (LRRC)) were included. There was total sacrectomy in 9 (incl. combined L5 en bloc spondylectomy in 2), partial in 10 and hemisacrectomy in 8 patients. In 12 patients, resection was navigation-assisted. For reconstruction, an omentoplasty, VRAM-flap or spinopelvic fixation was performed in 20, 10 and 13 patients, respectively.

RESULTS

With a median follow-up (FU) of 15 months, the FU rate was 93%. R0-resection was seen in 81.5% (no significant difference using navigation), and 81.5% of patients suffered from one or more minor-to-moderate complications (especially wound-healing disorders/infection). The median overall survival was 70 months. Local recurrence occurred in 20%, while 44% developed metastases and five patients died of disease.

CONCLUSIONS

Resection of sacral tumors is challenging and associated with a high complication profile. Interdisciplinary cooperation with visceral/vascular and plastic surgery is essential. In chordoma patients, systemic tumor control is favorable compared to LRRC and sarcomas. Navigation offers gain in intraoperative orientation, even if there currently seems to be no oncological benefit. Complete surgical resection offers long-term survival to patients undergoing sacrectomy for a variety of complex diseases.

Is 3D-printed self-stabilizing endoprosthesis reconstruction without supplemental fixation following total sacrectomy a viable approach for sacral tumours?

PURPOSE

The spinopelvic reconstruction poses significant challenges following total sacrectomy in patients with malignant or aggressive benign bone tumours encompassing the entire sacrum. In this study, we aim to assess the functional outcomes and complications of an integrated 3D-printed sacral endoprostheses featuring a self-stabilizing design, eliminating the requirement for supplemental fixation.

METHODS

We retrospectively analyzed patients with sacral tumours who underwent total sacrectomy followed by reconstruction with 3D-printed self-stabilizing endoprosthesis. Clinically, we evaluated functional outcomes using the 1993 version of the musculoskeletal tumour society (MSTS-93) score. Perioperative and postoperative complications were also documented.

RESULTS

10 patients met final inclusion criteria. The median age was 49 years (range, 31-64 years). The median follow-up time was 26.5 months (range, 15-47 months). Median postoperative functional MSTS-93 was 22.5 (range, 13-25). The median operation time was 399.5 min (305-576 min), and the median intraoperative blood loss was and 3200 ml (2400-7800 ml). Complications include wound dehiscence in one patient, bowel, bladder, and sexual dysfunction in four patients, cerebrospinal fluid leak in one patient, and tumour recurrence in one patient. There were no mechanical complications related to the endoprosthesis at the last follow-up.

CONCLUSION

The utilization of 3D-printed self-stabilizing endoprosthesis proved to be a viable approach, yielding satisfactory short-term outcomes in patients undergoing total sacral reconstruction without supplemental fixation.

The biomechanical effect of lumbopelvic distance reduction on reconstruction after total sacrectomy: a comparative finite element analysis of four techniques

BACKGROUND CONTEXT

Following total sacrectomy, lumbopelvic reconstruction is essential to restore continuity between the lumbar spine and pelvis. However, to achieve long-term clinical stability, bony fusion between the lumbar spine and the pelvic ring is crucial. Reduction of the lumbopelvic distance can promote successful bony fusion. Although many lumbopelvic reconstruction techniques (LPRTs) have been previously analyzed, the biomechanical effect of lumbopelvic distance reduction (LPDR) has not been investigated yet.

PURPOSE

To evaluate and compare the biomechanical characteristics of four different LPRTs while considering the effect of LPDR.

STUDY DESIGN/SETTING

A comparative finite element (FE) study.

METHODS

The FE models following total sacrectomy were developed to analyze four different LPRTs, with and without LPDR. The closed-loop reconstruction (CLR), the sacral-rod reconstruction (SRR), the four-rod reconstruction (FRR), and the improved compound reconstruction (ICR) techniques were analyzed in flexion, extension, lateral bending, and axial rotation. Lumbopelvic stability was assessed through the shift-down displacement and the relative sagittal rotation of L5, while implant safety was evaluated based on the stress state at the bone-implant interface and within the rods.

RESULTS

Regardless of LPDR, both the shift-down displacement and relative sagittal rotation of L5 consistently ranked the LPRTs as ICR

CONCLUSIONS

LPDR significantly improved both lumbopelvic stability and implant safety in all reconstruction techniques after total sacrectomy. LPDR reduced the shift-down displacement of L5, the relative sagittal rotation of L5, and the stress values at the bone-implant interface. Furthermore, in the ICR and SRR techniques, LPDR decreased the peak stress values within the rods. All four investigated LPRTs demonstrated suitability for lumbopelvic reconstruction, with the ICR technique exhibiting the highest lumbopelvic stiffness.

CLINICAL SIGNIFICANCE

LPDR creates a biomechanically advantageous environment following total sacrectomy; therefore, it has the potential to impact the design of custom-made 3D-printed or traditional LPRTs. However, to confirm the findings of the current FE study, long-term clinical trials are recommended.

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Key Words

• Biomechanics
• Finite element analysis
• Lumbopelvic distance reduction
• Lumbopelvic fixation
• Lumbopelvic reconstruction
• Lumbopelvic stabilization
• Total sacrectomy

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Affiliation(s)

Mate Turbucz School of PhD Studies, Semmelweis University, Üllői Str. 26, Budapest, Hungary; In Silico Biomechanics Laboratory, National Center for Spinal Disorders, Királyhágó Str. 1-3, Budapest, Hungary
Agoston Jakab Pokorni School of PhD Studies, Semmelweis University, Üllői Str. 26, Budapest, Hungary; In Silico Biomechanics Laboratory, National Center for Spinal Disorders, Királyhágó Str. 1-3, Budapest, Hungary
Benjamin Hajnal School of PhD Studies, Semmelweis University, Üllői Str. 26, Budapest, Hungary; In Silico Biomechanics Laboratory, National Center for Spinal Disorders, Királyhágó Str. 1-3, Budapest, Hungary
Kristof Koch School of PhD Studies, Semmelweis University, Üllői Str. 26, Budapest, Hungary; National Center for Spinal Disorders, Királyhágó Str. 1-3, Budapest, Hungary
Zsolt Szoverfi National Center for Spinal Disorders, Királyhágó Str. 1-3, Budapest, Hungary
Peter Pal Varga National Center for Spinal Disorders, Királyhágó Str. 1-3, Budapest, Hungary
Aron Lazary National Center for Spinal Disorders, Királyhágó Str. 1-3, Budapest, Hungary; Department of Spine Surgery, Department of Orthopaedics, Semmelweis University, Üllői Str. 78/b, Budapest, Hungary
Peter Endre Eltes In Silico Biomechanics Laboratory, National Center for Spinal Disorders, Királyhágó Str. 1-3, Budapest, Hungary; National Center for Spinal Disorders, Királyhágó Str. 1-3, Budapest, Hungary; Department of Spine Surgery, Department of Orthopaedics, Semmelweis University, Üllői Str. 78/b, Budapest, Hungary.

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Advances in Virtual Cutting Guide and Stereotactic Navigation for Complex Tumor Resections of the Sacrum and Pelvis: Case Series with Short-Term Follow-Up

Primary malignancies of the sacrum and pelvis are aggressive in nature, and achieving negative margins is essential for preventing recurrence and improving survival after en bloc resections. However, these are particularly challenging interventions due to the complex anatomy and proximity to vital structures. Using virtual cutting guides to perform navigated osteotomies may be a reliable method for safely obtaining negative margins in complex tumor resections of the sacrum and pelvis. This study details the technique and presents short-term outcomes. Patients who underwent an en bloc tumor resection of the sacrum and/or pelvis using virtual cutting guides with a minimum follow-up of two years were retrospectively analyzed and included in this study. Preoperative computer-assisted design (CAD) was used to design osteotomies in each case. Segmentation, delineating the tumor from normal tissue, was performed by the senior author using preoperative CT scans and MRI. Working with a team of biomedical engineers, virtual surgical planning was performed to create osteotomy lines on the preoperative CT and overlaid onto the intraoperative CT. The pre-planned osteotomy lines were visualized as "virtual cutting guides" providing real-time stereotactic navigation. A precision ultrasound-powered cutting tool was then integrated into the navigation system and used to perform the osteotomies in each case. Six patients (mean age 52.2 ± 17.7 years, 2 males, 4 females) were included in this study. Negative margins were achieved in all patients with no intraoperative complications. Mean follow-up was 38.0 ± 6.5 months (range, 24.8-42.2). Mean operative time was 1229 min (range, 522-2063). Mean length of stay (LOS) was 18.7 ± 14.5 days. There were no cases of 30-day readmissions, 30-day reoperations, or 2-year mortality. One patient was complicated by flap necrosis, which was successfully treated with irrigation and debridement and primary closure. One patient had local tumor recurrence at final follow-up and two patients are currently undergoing treatment for metastatic disease. Using virtual cutting guides to perform navigated osteotomies is a safe technique that can facilitate complex tumor resections of the sacrum and pelvis.

The evolution of oncovascular pelvic surgery: A historical perspective

Pelvic exenteration surgery has evolved dramatically in recent decades and now represents the standard of care for many patients with advanced pelvic malignancy. Most recently the use of complex vascular resection and reconstructive techniques have been applied in advanced pelvic oncology surgery at specialist units and these oncovascular techniques are considered one of the frontiers in this field. This article summaries the historical evolution of oncovascular surgery in the pelvis and sets the scene for where this treatment is going. The role of vascular resection and reconstruction in curative treatment of advanced pelvic malignancy is an evolving area that is redefining the boundaries of what was historically thought possible.

A novel three dimensional-printed biomechanically evaluated patient-specific sacral implant in spinopelvic reconstruction after total en bloc sacrectomy

Background: Reconstruction after a total sacrectomy is a challenge due to the special anatomical and biomechanical factors. Conventional techniques of spinal-pelvic reconstruction do not reconstruct satisfactorily. We describe a novel three-dimensional-printed patient-specific sacral implant in spinopelvic reconstruction after total en bloc sacrectomy. Methods: We performed a retrospective cohort study including 12 patients with primary malignant sacral tumors, including 5 men and 7 women with a mean age of 58.25 years (range 20-66 years), undergoing total en bloc sacrectomy with 3D printed implant reconstruction from 2016 to 2021. There were 7 cases of chordoma, 3 cases of osteosarcoma, 1 case of chondrosarcoma and 1 case of undifferentiated pleomorphic sarcoma. We use CAD technology to determine surgical resection boundaries, design cutting guides, and individualized prostheses, and perform surgical simulations before surgery. The implant design was biomechanically evaluated by finite element analysis. Operative data, oncological and functional outcomes, complications, and implant osseointegration status of 12 consecutive patients were reviewed. Results: The implants were implanted successfully in 12 cases without death or severe complications during the perioperative period. Resection margins were wide in 11 patients and marginal in one patient. The average blood loss was 3875 mL (range, 2000-5,000 mL). The average surgical time was 520 min (range, 380-735 min). The mean follow-up was 38.5 months. Nine patients were alive with no evidence of disease, two patients died due to pulmonary metastases, and one patient survived with disease due to local recurrence. Overall survival was 83.33% at 24 months. The Mean VAS was 1.5 (range, 0-2). The mean MSTS score was 21 (range, 17-24). Wound complications occurred in 2 cases. A deep infection occurred in one patient and the implant was removed. No implant mechanical failure was identified. Satisfactory osseointegration was found in all patients, with a mean fusion time of 5 months (range 3-6 months). Conclusion: The 3D-printed custom sacral prosthesis has been effective in reconstructing spinal-pelvic stability after total en bloc sacrectomy with satisfactory clinical outcomes, excellent osseointegration, and excellent durability.

Modified Iliac Screw in Lumbopelvic Fixation After Sacral Tumor Resection: A Single-Center Case Series

BACKGROUND

Traditional iliac screw, S2-alar iliac screw, and modified iliac screw are the 3 common techniques for lumbopelvic fixation. The application of the modified iliac technique in sacral spinal tumors has been rarely reported.

OBJECTIVE

To report the feasibility and safety of modified iliac screws after sacral tumor resection and their preliminary clinical outcomes.

METHODS

Twenty-seven patients who underwent sacral tumor resection with modified iliac screw fixation between August 2017 and August 2021 at our center were clinically and radiographically evaluated.

RESULTS

A total of 59 iliac screws were inserted by freehand according to the anatomic landmarks. The mean operation time was 207 minutes (range, 140-435 minutes). The average estimated blood loss was 1396 mL (300-4200 mL). Computed tomography scans showed that 2 (3.4%) screws penetrated the iliac cortex, indicating a 96.6% implantation accuracy rate. There were no iatrogenic neurovascular or visceral structure complications observed. The mean minimal distances from the screw head to the skin were 24.9 and 25.8 mm on the left and right sides, respectively. The mean minimal distances from the screw head to the horizontal level of the posterior superior iliac spine were 7.9 and 8.3 mm on the left and right sides, respectively. Two patients (7.4%) underwent reoperation for wound infection. At the latest follow-up, no patient had complications of screw head prominence, pseudarthrosis, or instrument failure.

CONCLUSION

The modified iliac screw is characterized by its minimal invasiveness and simplicity of placement. It is an ideal alternative for lumbopelvic fixation after sacral tumor resection.

A novel three-dimensional-printed patient-specific sacral implant for spinopelvic reconstruction in sacral giant cell tumour

PURPOSE

Spinopelvic reconstruction after sacral tumour resection is one of the most demanding procedures in sacral tumour surgery. The aims of this study were to evaluate the feasibility of spinopelvic reconstruction with 3D-printed prostheses in sacral giant cell tumours and the clinical outcomes and complications at follow-up.

METHODS

We retrospectively analyzed ten consecutive patients with giant cell tumors of the sacrum who underwent intralesional nerve-sparing resection with curative intent and custom implant reconstruction between 2016 and 2021. There were four males and six females with a mean age of 40.2 years (range, 25-62 years) at surgery. A computer-aided-design implant was prepared using 3D printing technology that was both matched to the bone defect and biomechanically evaluated. A 3D-printed surgical guide was used to replicate the resection procedure as planned. We analyzed operational outcomes, oncological outcomes, functional outcomes, complications, and prosthetic outcomes. Pain at rest was assessed according to a 10-cm VAS score. The results of functional improvement were evaluated using the MSTS-93 score at the final follow-up.

RESULTS

All patients were observed for 26 to 61 months, with an average follow-up of 43.8 months. No deep infection or prosthetic structural failure occurred in this study. A total of 80% of patients had good neurological function and normal urinary, bowel, and ambulatory functions. The mean MSTS score was 24.1 (range, 22-26). The mean VAS score was 2 (range 0 to 2). Delayed wound healing occurred in three patients, and the wounds healed after debridement. One case had local recurrence and survived tumour-free after resection of the recurrent lesion. An aseptic loosening was found in a patient that did not require secondary surgery. By radiographical assessments, we found that 90% of implants were well osseointegrated at the final follow-up examination.

CONCLUSIONS

The 3D-printed sacral implants might provide a promising strategy for spinopelvic reconstruction in sacral giant cell tumours undergoing intralesional nerve-sparing surgery with satisfactory clinical outcomes, osseointegration, and excellent durability.

Reconstruction after hemisacrectomy with a novel 3D-printed modular hemisacrum implant in sacral giant cell tumor of the bone

Background: There are a limited but increasing number of case reports and series describing the use of 3D-printed prostheses in bone tumor surgery. Methods: We describe a new approach to performing nerve-preserving hemisacrectomy in patients with sacral giant cell tumors with reconstruction using a novel 3D-printed patient-specific modular prosthesis. The series included four female and two male patients with a mean age of 34 years (range, 28-42 years). Surgical data, imaging assessments, tumor and functional status, implant status, and complications were retrospectively analyzed in six consecutive patients. Results: In all cases, the tumor was removed by sagittal hemisacrectomy, and the prosthesis was successfully implanted. The mean follow-up time was 25 months (range, 15-32 months). All patients in this report achieved successful surgical outcomes and symptomatic relief without significant complications. Clinical and radiological follow-up showed good results in all cases. The mean MSTS score was 27.2 (range, 26-28). The average VAS was 1 (range, 0-2). No structural failures or deep infections were detected in this study at the time of follow-up. All patients had good neurological function. Two cases had superficial wound complications. Bone fusion was good with a mean fusion time of 3.5 months (range, 3-5 months). Conclusion: These cases describe the successful use of custom 3D-printed prostheses for reconstruction after sagittal nerve-sparing hemisacrectomy with excellent clinical outcomes, osseointegration, and durability.

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.

Biomechanical Analysis of the Tuning Fork Plate Versus Dual Pelvic Screws in a Sacrectomy Model: A Finite Element Study

STUDY DESIGN

To evaluate the mechanical effectiveness of "tuning fork" plate fixation system by comparing with dual iliac screw fixation under different spinal motion through finite element analysis (FEA).

OBJECTIVE

Lumbosacral deficiencies occur from birth defects or following destruction by tumors. The objective of this study was to evaluate the mechanical effectiveness of the tuning fork plate compared to dual iliac screw system which is the gold standard fixation in treating lumbosacral deficiencies. This is an innovative fixation device for treating lumbosacral deficiencies.

METHODS

The deficiency model was prepared using a previously developed and validated finite element T10-pelvis model. To create the lumbo-sacral deficiency the segments between L3 and sacrum were removed from the model. The model was then instrumented from T10 to L2 segments and the ilium using either the tuning fork plate or a dual iliac screw construct. With the ilium fixed, the T10 vertebrae was subjected to 10 Nm moment and 400 N follower load to simulate spinal motions. Range of motion (ROM) of spine and stresses on the instrumentation were calculated for 2 fixation devices and compared with each other.

RESULTS

The 2 fixation systems demonstrate a comparable motion reduction in all loading modes. Stress values were higher in the dual iliac screw constructs compared with the tuning fork plate fixation system. The factor of safety of the tuning fork plate device was higher than the dual iliac screw fixation by 50%.

CONCLUSIONS

Both fixation devices had similar performance in motion reduction at spine levels. However, based on predicted implant stresses there were less chances of implant failure in the fork plate fixation, compared to the dual iliac screw system.

Contemporary Management of Locally Advanced and Recurrent Rectal Cancer: Views from the PelvEx Collaborative

Pelvic exenteration is a complex operation performed for locally advanced and recurrent pelvic cancers. The goal of surgery is to achieve clear margins, therefore identifying adjacent or involved organs, bone, muscle, nerves and/or vascular structures that may need resection. While these extensive resections are potentially curative, they can be associated with substantial morbidity. Recently, there has been a move to centralize care to specialized units, as this facilitates better multidisciplinary care input. Advancements in pelvic oncology and surgical innovation have redefined the boundaries of pelvic exenterative surgery. Combined with improved neoadjuvant therapies, advances in diagnostics, and better reconstructive techniques have provided quicker recovery and better quality of life outcomes, with improved survival This article provides highlights of the current management of advanced pelvic cancers in terms of surgical strategy and potential future developments.

Management of chordoma of the sacrum and mobile spine

Chordoma is a very rare, poorly known malignancy, with slow progression, mainly located in the sacrum and spine. All age groups may be affected, with a diagnostic peak in the 5th decade of life. Clinical diagnosis is often late. Histologic diagnosis is necessary, based on percutaneous biopsy. Specific markers enable diagnosis and prediction of response to novel treatments. New radiation therapy techniques can stabilize the tumor for 5 years in inoperable patients, but en-bloc resection is the most effective treatment, and should be decided on after a multidisciplinary oncology team meeting in an expert reference center. The type of resection is determined by fine analysis of invasion. According to the level of resection, the patients should be informed and prepared for the expected vesico-genito-sphincteral neurologic sequelae. In tumors not extending above S3, isolated posterior resection is possible. Above S3, a double approach is needed. Anterior release of the sacrum is performed laparoscopically or by robot; resection uses a posterior approach. Posterior wall reconstruction is performed, with an associated flap. Spinopelvic stabilization is necessary in trans-S1 resection. Total or partial sacrectomy shows high rates of complications: intraoperative blood loss, infection or mechanical issues. Neurologic sequelae depend on the level of root sacrifice. No genital-sphincteral function survives S3 root sacrifice. Patient survival depends on initial resection quality and the center's experience. Immunotherapy is an ongoing line of research.

Use of a 3D-Printed Patient-Specific Surgical Jig and Ready-Made Total Sacral Endoprosthesis for Total Sacrectomy and Reconstruction

Objective

In the present study, the authors aimed to optimize the workflow of utilizing a 3D printing technique during surgical treatment for malignant sacral tumors, mainly on preparation of patient-specific surgical jigs and ready-made 3D-printed total sacral endoprosthesis.

Methods

Three patients with a malignant sacral tumor received total sacrectomy with preoperative design of a patient-specific 3D-printed cutting jig and endoprosthetic reconstruction. Size of ready-made 3D-printed endoprosthesis was determined based on preoperative images, planned surgical margin, and size of the endoprosthesis. A patient-specific cutting jig was designed with a bilateral cutting slot matching the bilateral planes of the implant precisely. The tumor was removed en bloc through a single posterior approach only, being followed by reconstruction with ready-made total sacral endoprosthesis.

Results

The mean time for preoperative design and manufacture of the surgical jig was 6.3 days. Surgical jigs were successfully used during surgery and facilitated the osteotomy. The mean operation time was 177 minutes (range 150-190 minutes). The mean blood loss was 3733 ml (range 3600-4000 ml). R0 resections were achieved in all the three cases proven by pathology. Evaluation of osteotomy accuracy was conducted by comparing preoperative plans and postoperative CT scans. The mean osteotomy deviation was 2.1 mm (range 0-4 mm), and mean angle deviation of osteotomy was 3.2° (range 0-10°). At a mean follow-up of 18.7 months, no local recurrence was observed. One patient had lung metastasis 15 months after surgery. Two patients were alive with no evidence of the disease.

Conclusions

The patient-specific surgical jig and ready-made 3D-printed total sacral endoprosthesis can shorten the surgical preparation time preoperatively, facilitating accurate osteotomy and efficient reconstruction intraoperatively. The workflow seems to be feasible and practical.

Sacrectomy for sacral tumors: perioperative outcomes in a large-volume comprehensive cancer center

BACKGROUND CONTEXT

Sacral tumors are incredibly rare lesions affecting fewer than one in every 10,000 persons. Reported perioperative morbidity rates range widely, varying from 30% to 70%, due to the relatively low volumes seen by most centers. Factors affecting perioperative outcome following sacrectomy remain ill-defined.

PURPOSE

To characterize perioperative outcomes of sacral tumor patients undergoing sacrectomy and identify independent risk factors of perioperative morbidity STUDY DESIGN/SETTING: Retrospective cohort study at a single comprehensive cancer center PATIENT SAMPLE: Consecutively treated sacral tumor patients (primary or metastatic) undergoing sacrectomy for oncologic resection between April 2013 and April 2020 OUTCOME MEASURES: Perioperative complications, hospital length of stay, non-home discharge, 30-day readmission, and 30-day reoperation METHODS: Details were gathered about tumor pathology and morphology, surgery performed, baseline medical comorbidities, preoperative lab data, and patient demographics. Stepwise multivariable regressions were conducted to identify independent risk factors of perioperative outcomes while evaluating predictive accuracy.

RESULTS

57 sacral tumor patients were included (mean age 55.5±13.0 years; 60% female). The complication, non-home discharge, 30-day readmission, and 30-day reoperation rates were 39%, 56%, 16%, and 14%, respectively. Independent predictors of perioperative complications included ASA>2 (OR=10.7; 95%CI [1.3, 86.0]; p=0.026), radicular pain (OR=10.9; p=0.014), platelet count (OR=0.989 per 10³/μL; p=0.049), and instrumentation (OR=10.7; p=0.009). Independent predictors of length of stay included iliac vessel involvement (β=15.8; p=0.005), larger tumor volume (β=0.027 per cm³; p<0.001), a staged procedure (β=10.0; p=0.018), and S1 nerve root sacrifice (OR=15.8; p=.011). The optimal model predictive of non-home discharge included bilateral S3-S5 or higher nerve root sacrifice (OR=3.9; p=0.054), instrumentation (OR=8.6; p=0.005), and vertical rectus abdominis musculocutaneous flap closure (OR=5.3; p=0.067). 30-day readmission was independently predicted by history of chronic kidney disease (OR=26.7; p=0.021), radicular pain (OR=8.1; p=0.039), and preoperative saddle anesthesia (OR=12.6; p=0.026). All multivariable models achieved good discrimination (AUC>0.8 and R²>0.7).

CONCLUSION

Clinical and operative factors were important predictors of complications and 30-day readmission, while tumor-related and operative factors accounted for most of the variability in length of stay and non-home discharge.

Comparison of free vascularized fibular flaps and allograft fibular strut grafts to supplement spinopelvic reconstruction for sacral malignancies

AIMS

Orthopaedic and reconstructive surgeons are faced with large defects after the resection of malignant tumours of the sacrum. Spinopelvic reconstruction is advocated for resections above the level of the S1 neural foramina or involving the sacroiliac joint. Fixation may be augmented with either free vascularized fibular flaps (FVFs) or allograft fibular struts (AFSs) in a cathedral style. However, there are no studies comparing these reconstructive techniques.

METHODS

We reviewed 44 patients (23 female, 21 male) with a mean age of 40 years (SD 17), who underwent en bloc sacrectomy for a malignant tumour of the sacrum with a reconstruction using a total (n = 20), subtotal (n = 2), or hemicathedral (n = 25) technique. The reconstructions were supplemented with a FVF in 25 patients (57%) and an AFS in 19 patients (43%). The mean length of the strut graft was 13 cm (SD 4). The mean follow-up was seven years (SD 5).

RESULTS

There was no difference in the mean age, sex, length of graft, size of the tumour, or the proportion of patients with a history of treatment with radiotherapy in the two groups. Reconstruction using an AFS was associated with nonunion (odds ratio 7.464 (95% confidence interval (CI) 1.77 to 31.36); p = 0.007) and a significantly longer mean time to union (12 months (SD 3) vs eight (SD 3); p = 0.001) compared with a reconstruction using a FVF. Revision for a pseudoarthrosis was more likely to occur in the AFS group compared with the FVF group (hazard ratio 3.84 (95% CI 0.74 to 19.80); p = 0.109); however, this was not significant. Following the procedure, 32 patients (78%) were mobile with a mean Musculoskeletal Tumor Society Score 93 of 52% (SD 24%). There was a significantly higher mean score in patients reconstructed with a FVF compared with an AFS (62% vs 42%; p = 0.003).

CONCLUSION

Supplementation of spinopelvic reconstruction with a FVF was associated with a shorter time to union and a trend towards a reduced risk of hardware failure secondary to nonunion compared with reconstruction using an AFS. Spinopelvic fixation supplemented with a FVF is our preferred technique for reconstruction following resection of a sacral tumour. Cite this article: Bone Joint J 2021;103-B(8):1414-1420.

Sacroplasty Augmentation of Instrumented Pelvic Reconstruction After High Sacrectomy: A Technical Case Report

BACKGROUND AND IMPORTANCE

En bloc resection of sacral tumors is the most effective treatment to help prevent recurrence. Sacrectomy, however, can be destabilizing, depending on the extent of resection. Various surgical techniques for improving stability and enabling early ambulation have been proposed.

CLINICAL PRESENTATION

Here, we report a case in which we use PMMA (poly[methyl methacrylate]) to augment pelvic instrumentation to improve mechanical stability after sacrectomy for en bloc resection of a solitary fibrous tumor.

CONCLUSION

We highlight the use of sacroplasty augmentation of pelvic ring reconstruction to provide biomechanical stability without the need for fusion of any mobile spine segments, which allowed for early patient ambulation and no appreciable loss of range of motion or mobility.

Free Vascularized Fibula Flap Reconstruction of Total and Near-total Destabilizing Resections of the Sacrum

BACKGROUND

Vascularized bone grafts (VBGs) are associated with improved union and fewer instrumentation complications in the mobile spine. It is not known if VBGs are similarly efficacious after sacrectomy.

METHODS

We conducted a retrospective chart review of all patients who underwent total sacrectomy and immediate reconstruction with VBG between 2005 and 2019. Patient and surgical characteristics in addition to union and functional outcomes were analyzed.

RESULTS

We identified 10 patients (6 women and 4 men) with a mean age of 42 years (range, 12-71 years). All patients received iliolumbar instrumentation as well as a free fibula flap as a VBG. There were no complications at the fibula flap donor site or specifically related to the VBG. Bony union was achieved in 7 (88%) of 8 patients with an average union time of 6.3 months (range, 2-10 months). Surgical complications occurred in 5 patients, 4 patients required reoperation for wound dehiscence, and 1 patient required conversion to a 4-rod construct and bone grafting for instrumentation loosening and partial nonunion. Instrumentation failure developed in 1 patient, but no surgical intervention was required. One patient was able to walk independently without any limitation, 5 patients required a walker, 2 were wheelchair-bound except for short (<15 ft) distances, and 2 were lost to follow-up.

CONCLUSIONS

The free vascularized fibula flap is a safe and effective option for supplementing spinal reconstruction after destabilizing sacrectomy.

Clinical Statistical Analysis with Comparison between Pelvic and Non-pelvic Chondrosarcoma

Objectives

Chondrosarcomas are rare tumors with a variable biological characteristic. Their treatment clinically and surgically is controversial. Analysis of the clinical statistics and prognostic factors of pelvic chondrosarcoma provides a reference for clinical diagnosis and treatment.

Methods

A total of 73 cases of chondrosarcoma were collected, including 24 pelvic samples, from 2008 to 2017 from the hospital database and divided into two groups: pelvic chondrosarcoma and non-pelvic chondrosarcoma. The clinical characteristics and prognostic factors of pelvic chondrosarcoma were analyzed using different statistical methods.

Results

Among the 24 pelvic chondrosarcoma patients, the ratio of male to female was 1.4:1, and the median age was 43.5 years. According to the classification proposed by Enneking, there were five grade I, 14 grade II, and five grade III. Histological grading of chondrosarcoma was grade I in one case, II in 15 cases, and III in eight cases. The histological type was 17 conventional, three dedifferentiated, two secondary, one myxoid, and one mesenchymal. The overall survival rates for 24 cases at three, five, and 10 years were 82.2±8.1%, 77.3±8.9%, and 52.4±12.1%, respectively. The local recurrence rate of pelvic chondrosarcoma after surgical resection (83.3%) was significantly higher than that of other sites (34.7%), and the difference was statistically significant (p < 0.001). The final proportion of amputation rate (50.0%) was also higher than other parts (20.4%), with a statistically significant difference (p = 0.010). The total survival of the two groups was not significantly different (p = 0.216).

Conclusions

Chondrosarcoma of bone generally has an excellent prognosis when optimally diagnosed and treated by an experienced team of specialists. Pelvic chondrosarcoma has a higher local recurrence rate than the other sites and tends to result in amputation. Early local recurrence after surgery indicates a poor prognosis.

Novel Graft Technique for Lumbopelvic Reconstruction After Sacral Tumor Resection: A Case Report

CASE

Reconstruction after sacral tumor resection carries a high risk of nonunion and requires a slow return to weight-bearing. A bilateral iliac-crest graft, mobilized on a muscular pedicle, was used to graft and fuse the spine and pelvis after resection of a massive sacral schwannoma. Long-term follow-up and three-dimensional computed tomography imaging demonstrate rapid incorporation and solid fusion, with hypertrophy of the graft struts and excellent return to function.

CONCLUSION

This novel graft technique provides structural autograft bone that bridges the iliolumbar resection gap, providing a vascularized autograft that incorporates rapidly and reliably.

Total sacrectomy with a combined antero-posterior surgical approach for malignant sacral tumours

Purpose

To investigate the indications, approaches, resection methods, and complications of total sacrectomy with a combined antero-posterior approach for malignant sacral tumours.

Methods

Fourteen cases of primary malignant sacral tumours treated with total sacrectomy between January 2012 and 2018 were retrospectively analysed. All patients presented with pre-operative lumbosacral pain or constipation. A combined antero-posterior approach was used for tumour resection, and the spinal pedicle screw rod system was used to achieve ilio-lumbar stability. The visual analogue scale (VAS) and Musculoskeletal Tumor Society (MSTS) scores were used to assess pain and lower limb function, respectively. The mean operative time and intra-operative blood loss were 6.54 hours and 2935 mL, respectively. The mean follow-up period was 62 months.

Results

None of the patients died peri-operatively. At the last follow-up, ten patients were continuously disease-free, three were alive with disease, and one died of disease from lung metastasis. Tumour recurrence occurred in three patients. The MSTS scores ranged from 6 to 28 (20.00–93.33%, 6/30–28/30) with an average of 20 (66.67%, 20/30). Seven patients could walk independently in public, five could only walk at home using a walking aid, and two could only lie down and stand for a short time. Thirteen patients developed post-operative complications such as skin necrosis, screw loosening, connecting rod fracture, neuropathic pain, sciatic nerve injury, dysuria, and urinary incontinence.

Conclusion

Total sacrectomy can effectively treat malignant sacral tumours with good resection boundaries and prognosis. However, the high incidence of post-operative complications may impact post-operative neurological function.

Chordoma-Current Understanding and Modern Treatment Paradigms

Chordoma is a low-grade notochordal tumor of the skull base, mobile spine and sacrum which behaves malignantly and confers a poor prognosis despite indolent growth patterns. These tumors often present late in the disease course, tend to encapsulate adjacent neurovascular anatomy, seed resection cavities, recur locally and respond poorly to radiotherapy and conventional chemotherapy, all of which make chordomas challenging to treat. Extent of surgical resection and adequacy of surgical margins are the most important prognostic factors and thus patients with chordoma should be cared for by a highly experienced, multi-disciplinary surgical team in a quaternary center. Ongoing research into the molecular pathophysiology of chordoma has led to the discovery of several pathways that may serve as potential targets for molecular therapy, including a multitude of receptor tyrosine kinases (e.g., platelet-derived growth factor receptor [PDGFR], epidermal growth factor receptor [EGFR]), downstream cascades (e.g., phosphoinositide 3-kinase [PI3K]/protein kinase B [Akt]/mechanistic target of rapamycin [mTOR]), brachyury—a transcription factor expressed ubiquitously in chordoma but not in other tissues—and the fibroblast growth factor [FGF]/mitogen-activated protein kinase kinase [MEK]/extracellular signal-regulated kinase [ERK] pathway. In this review article, the pathophysiology, diagnosis and modern treatment paradigms of chordoma will be discussed with an emphasis on the ongoing research and advances in the field that may lead to improved outcomes for patients with this challenging disease.

Chordoma of the sacrum and mobile spine: a narrative review

Chordoma is a notochord-derived primary tumor of the skull base and vertebral column known to affect 0.08 to 0.5 per 100,000 persons worldwide. Patients commonly present with mechanical, midline pain with or without radicular features secondary to nerve root compression. Management of these lesions has classically revolved around oncologic resection, defined by en bloc resection of the lesion with negative margins as this was found to significantly improve both local control and overall survival. With advancement in radiation modalities, namely the increased availability of focused photon therapy and proton beam radiation, high-dose (>50 Gy) neoadjuvant or adjuvant radiotherapy is also becoming a standard of care. At present chemotherapy does not appear to have a role, but ongoing investigations into the ontogeny and molecular pathophysiology of chordoma promise to identify therapeutic targets that may further alter this paradigm. In this narrative review we describe the epidemiology, histopathology, diagnosis, and treatment of chordoma.

Surgical Strategy for Sacral Tumor Resection

PURPOSE

This study aimed to present our experiences with a precise surgical strategy for sacrectomy.

MATERIALS AND METHODS

This study comprised a retrospective review of 16 patients (6 males and 10 females) who underwent sacrectomy from 2011 to 2019. The average age was 42.4 years old, and the mean follow-up period was 40.8 months. Clinical data, including age, sex, history, pathology, radiographs, surgical approaches, onset of recurrence, and prognosis, were analyzed.

RESULTS

The main preoperative symptom was non-specific local pain. Nine patients (56%) complained of bladder and bowel symptoms. All patients required spinopelvic reconstruction after sacrectomy. Three patients, one high, one middle, and one hemi-sacrectomy, underwent spinopelvic reconstruction. The pathology findings of tumors varied (chordoma, n=7; nerve sheath tumor, n=4; giant cell tumor, n=3, etc.). Adjuvant radiotherapy was performed for 5 patients, chemotherapy for three, and combined chemoradiotherapy for another three. Six patients (38%) reported postoperative motor weakness, and newly postoperative bladder and bowel symptoms occurred in 5 patients. Three patients (12%) experienced recurrence and expired.

CONCLUSION

In surgical resection of sacral tumors, the surgical approach depends on the size, location, extension, and pathology of the tumors. The recommended treatment option for sacral tumors is to remove as much of the tumor as possible. The level of root sacrifice is a predicting factor for postoperative neurologic functional impairment and the potential for morbidity. Pre-operative angiography and embolization are recommended to prevent excessive bleeding during surgery. Spinopelvic reconstruction must be considered following a total or high sacrectomy or sacroiliac joint removal.

Reconstruction of Shattered Lumbo-Sacral Junction/Pelvis Utilizing Bilateral L4-Sacrum Fibula Strut Allograft And Double Iliac Screws Plus Routine Lumbar Pedicle Screw Fixation

Background:

A traumatically shattered lumbosacral junction/pelvis may be difficult to repair. Here the authors offer a pelvic fixation technique utilizing routine pedicle screws, interbody lumbar fusions, bilateral iliac screws/ rods/crosslinks, and bilateral fibular strut allografts from the lumbar spine to the sacrum.

Methods:

A middle aged male sustained a multiple storey fall resulting in a left sacral fracture, and right sacroiliac joint (SI) dislocation. The patient had previously undergone attempted decompressions with routine pedicle screw L4-S1 fusions at outside institutions; these failed twice. When the patient was finally seen, he exhibited, on CT reconstructed images, MR, and X-rays, a left sacral fracture nonunion, and a right sacroiliac joint dislocation.

Results:

The patient underwent a bilateral pelvic reconstruction utilizing right L4, L5, S1 and left L4, L5 pedicle screws plus interbody fusions (L4-L5, and L5, S1), performed from the left. Unique to this fusion construct was the placement of bilateral double iliac screws plus the application of bilateral fibula allografts from L4-sacrum filled with bone morphogenetic protein (BMP). After rod/screw/connectors were applied, bone graft was placed over the fusion construct, including the decorticated edges of the left sacral fractures, and right SI joint dislocation. We additionally reviewed other pelvic fusion reconstruction methods.

Conclusions:

Here, we utilized a unique pelvic reconstruction technique utilizing pedicle screws/rods, double iliac screws/rods, and bilateral fibula strut grafts extending from the L4-sacrum filled with BMP.

Compassionate use of a custom 3D-printed sacral implant for revision of failing sacrectomy: case report

Reconstruction of the spinopelvic continuity after sacral resection for primary sacral tumors remains challenging. Complex anatomical and biomechanical factors of this transition zone may be addressed with the advancement of 3D-printed implants. Here, the authors report on a 67-year-old patient with a sacral chordoma who initially underwent total en bloc sacrectomy followed by standard spinopelvic reconstruction. Pseudarthrosis and instrumentation failure of the lumbosacral junction construct subsequently developed. A custom 3D-printed sacral prosthesis was created using high-resolution CT images. Emergency Food and Drug Administration approval was obtained, and the custom device was implanted as a salvage reconstruction surgery. Made of porous titanium mesh, the custom artificial sacrum was placed in the defect based on the anticipated osteotomic planes and was fixed with a screw-rod system along with a fibular bone strut graft. At the 18-month follow-up, the patient was disease free and walking short distances with assistance. CT revealed excellent bony incorporation into the graft.The use of a custom 3D-printed prosthesis in spinal reconstruction has been rarely reported, and its application in sacral reconstruction and long-term outcome are novel. While the implant was believed to be critical in endowing the region with enough biomechanical stability to promote healing, the procedure was difficult and several key learning points were discovered along the way.

[Treatment concepts for complications after resection and defect reconstruction of pelvic tumours]

BACKGROUND

Partial pelvic resection, internal hemipelvectomy or sacrectomy as a result of bone sarcoma is still challenging. No matter what kind of reconstruction is used, there is still a much higher rate of complications in pelvic surgery compared to sarcoma surgery of the long bones.

OBJECTIVES

We describe the most common complications in pelvic sarcoma surgery and specific complications related to the reconstruction method. Handling strategies for these complications are specified.

METHODS

We performed a literature search and report our own experiences in the troubleshooting of pelvic surgery-related complications to gain an up-to-date overview of the state-of-the-art in management strategies.

RESULTS

Prospective randomized trials or meta-analyses on this topic are lacking. The literature search depicted that, besides local recurrence, deep infection after reconstruction is the most serious complication. An early revision with radical debridement has to be performed in order to save the reconstruction. In the case of a deep infection, the removal of all implants with a total loss of the reconstruction is often unavoidable. Therefore, an individualized risk-benefit analysis prior to surgery with respect to the type of reconstruction, or no reconstruction at all (hip transposition), together with the patient is advisable.

CONCLUSIONS

Complications-especially infections-after hemipelvectomy or sacrectomy are common. In the case of infection, in some cases, an early revision is the only chance to prevent a reconstruction from explantation.

One-Step Reconstruction with a Novel Suspended, Modular, and 3D-Printed Total Sacral Implant Resection of Sacral Giant Cell Tumor with Preservation of Bilateral S1-3 Nerve Roots via a Posterior-Only Approach

Objective

To investigate the efficacy and safety of spinopelvic reconstruction based on a novel suspended, modular, and 3D‐printed total sacral implant after total piecemeal resection of a sacral giant cell tumor (SGCT) with the preservation of bilateral S_1–3 nerve roots via a posterior‐only approach.

Methods

Five patients who had undergone total piecemeal resection of SGCT involving upper sacral segments (S₁ and S₂) and the midline with the preservation of bilateral S_1–3 nerve roots via a posterior‐only approach between September 2017 and July 2018 were retrospectively reviewed. A novel suspended, modular, and 3D‐printed total sacral implant had been used for reconstruction. This series included two female and three male patients, with a mean age of 42.2 years (range, 31–53 years). Surgical time, blood loss, complications, preoperative and postoperative neurological function, instrumentation failure, and local control were presented and analyzed.

Results

All patients underwent the operation without death or serious complications. The implant was installed on the defect, connecting the ilium and lumbar vertebrae, and fixed with a screw–rod system up to the level of L_3–4 or L_4–5. The mean operative time was 502 min (range, 360–640 min) and the mean operative blood loss 4400 mL (range, 3000–7000 mL). The mean follow‐up was 15 months. After the operation, pain was significantly relieved, and the patients resumed walking as early as 2 weeks later. The patients showed no neurogenic bladder dysfunction and no fecal incontinence or gait disturbance. Wound healing was poor in one patient. Patients recovered well without evidence of local recurrence. No implant failures or related clinical symptoms were detected during follow up. Satisfactory bone ingrowth and osseointegration at the bone‐implant junctions was found in follow‐up CT.

Conclusion

Although technically challenging, it is feasible and safe to use a suspended, modular, and 3D‐printed implant for reconstruction after total piecemeal resection with the preservation of bilateral S_1–3 nerve roots in patients with SGCT. We believe that this implant can be applied to sacral reconstruction in a wide variety of diseases.

Biomechanical comparison of a 3D-printed sacrum prosthesis versus rod-screw systems for reconstruction after total sacrectomy: A finite element analysis

BACKGROUND

Reconstruction after total sacrectomy is a difficult problem in the field of orthopedic oncology. Current reconstruction methods have not completely solved the problems associated with instrumentation failure. The purpose of this study was to evaluate the biomechanical properties of a 3D-printed total sacrum prosthesis and to conduct biomechanical comparisons between the total sacrum prosthesis and rod-screw systems for lumbosacral reconstruction after total sacrectomy.

METHODS

Three types of reconstruction were explored, and corresponding finite element models were simulated: four-rod reconstruction, four-rod plus anterior column reconstruction, and 3D-printed total sacrum prosthesis reconstruction. A vertical load of 600 N was applied to the L4 vertebra, and the bilateral acetabula were set as the boundary with six degrees of freedom fixed, simulating the bipedal standing position.

FINDINGS

The order of the reconstructions according to decreasing maximum von Mises stress was as follows: four-rod reconstruction > four-rod plus anterior column reconstruction >3D-printed total sacrum prosthesis reconstruction. The order of reconstructions according to decreasing L5 shift-down displacement was as follows: four-rod reconstruction >3D-printed total sacrum prosthesis reconstruction > four-rod plus anterior column reconstruction.

INTERPRETATION

Compared with the rod-screw systems, the total sacrum prosthesis reconstruction has the biomechanical advantages of a more uniform stress distribution, a lower peak stress and better stability and can thus serve as an alternative choice for reconstruction after total sacrectomy.

Dual iliac screws in spinopelvic fixation: a systematic review

PURPOSE

The classical spinopelvic fixation includes 1 iliac screw on each side. The purpose of this study is to specify the indications of the "dual iliac screw" (DIS) construct, i.e., when to put 2 iliac screws on each side, to describe its biomechanical advantages, and to define its related technical aspects.

METHODS

A primary search on Medline through PubMed distribution was performed, with the use of the terms "pelvic fixation" or "spinopelvic" or "lumbo-iliac" and the terms "dual iliac screw" or "double iliac screw." English papers corresponding to the inclusion criteria were analyzed regarding the specific indications of the DIS construct and its surgical technique and advantages.

RESULTS

Eleven papers were identified according to the research criteria and included in this review. Three main indications were identified for the DIS technique according to three types of pathologies: in adult deformities when a long construct is needed in an osteoporotic patient or when correction requires three-column osteotomy of the sacrum; in trauma when a U-shaped fracture-dislocation of the sacrum is involved; in sacral tumors when a sacrectomy is performed or when destructive metastatic lesions of the sacrum require palliative surgical treatment. Biomechanically, the DIS technique proved to have higher construct stiffness in terms of compression and torsion.

CONCLUSION

In specific cases, affecting different areas of spinal diseases, the DIS technique is more advantageous, when compared to the "single iliac screw" version, as it would provide a stronger and safer fixation at the base of the spinopelvic construct. These slides can be retrieved under Electronic Supplementary Material.

Reconstruction of the pelvic ring after total en bloc sacrectomy using a 3D-printed sacral endoprosthesis with re-establishment of spinopelvic stability: a retrospective comparative study

AIMS

The aim of this study was to describe the use of 3D-printed sacral endoprostheses to reconstruct the pelvic ring and re-establish spinopelvic stability after total en bloc sacrectomy (TES) and to review its outcome.

PATIENTS AND METHODS

We retrospectively reviewed 32 patients who underwent TES in our hospital between January 2015 and December 2017. We divided the patients into three groups on the basis of the method of reconstruction: an endoprosthesis group (n = 10); a combined reconstruction group (n = 14), who underwent non-endoprosthetic combined reconstruction, including anterior spinal column fixation; and a spinopelvic fixation (SPF) group (n = 8), who underwent only SPF. Spinopelvic stability, implant survival (IS), intraoperative haemorrhage rate, and perioperative complication rate in the endoprosthesis group were documented and compared with those of other two groups.

RESULTS

The mean overall follow-up was 22.1 months (9 to 44). In the endoprosthesis group, the mean intraoperative hemorrhage was 3530 ml (1600 to 8100). Perioperative complications occurred in two patients; both had problems with wound healing. After a mean follow-up of 17.7 months (12 to 38), 9/10 patients could walk without aids and 8/10 patients were not using analgesics. Imaging evidence of implant failure was found in three patients, all of whom had breakage of screws and/or rods. Only one of these, who had a local recurrence, underwent re-operation, at which solid bone-endoprosthetic osseointegration was found. The mean IS using re-operation as the endpoint was 32.5 months (95% confidence interval 23.2 to 41.8). Compared with the other two groups, the endoprosthesis group had significantly better spinopelvic stability and IS with no greater intraoperative haemorrhage or perioperative complications.

CONCLUSION

The use of 3D-printed endoprostheses for reconstruction after TES provides reliable spinopelvic stability and IS by facilitating osseointegration at the bone-implant interfaces, with acceptable levels of haemorrhage and complications. Cite this article: Bone Joint J 2019;101-B:880-888.

Robotic Surgery Assisted Staged En-Bloc Sacrectomy for Sacral Chordoma: A Case Report

CASE

Two male patients aged 37 years and 39 years, diagnosed with sacral chordoma, underwent robotic-assisted preparatory adhesiolysis from the anterior aspect of the tumor, followed by posterior en-bloc partial sacrectomy. The average total operative time was 360 minutes (anterior docking + anterior console + posterior excision), and mean blood loss was 930 mL. Both patients were mobilized early, had no postoperative complications, and were free of local recurrence at 18 month of follow-up.

CONCLUSIONS

Robotic-assisted surgery is a novel, valid, safe, and minimally invasive technique which drastically reduces the associated surgical complications of single-staged posterior sacrectomy, resulting in excellent functional and oncological outcome.

Factors Associated With Spinopelvic Fixation Mechanical Failure After Total Sacrectomy

STUDY DESIGN

We retrospectively analyzed factors associated with spinopelvic mechanical failure after total sacrectomy.

OBJECTIVE

To find the rate and type of mechanical fixation failure after total sacrectomy and to identify the associated risk factors.

SUMMARY OF BACKGROUND DATA

Although rigid fixation has been achieved, mechanical failure is sometimes encountered in reconstruction after total sacrectomy. The incidence and factors associated with spinopelvic fixation mechanical failure after total sacrectomy are still not clear.

METHODS

The study comprised 63 patients who underwent spinopelvic reconstruction after total sacrectomy. The potential risk factors for fixation mechanical failure after total sacrectomy were evaluated, which included age, sex, body mass index, type of tumor (benign or malignant), and adjuvant treatment received (e.g., chemotherapy, radiation therapy). The surgery-related factors included the classification of tumor resection (en bloc or piecemeal resection) and the type of iliosacral resection. Adoption of anterior spinal column fixation (ASCF), posterior pelvic ring fixation (PPRF), four-rod technique (FRT) of spinopelvic fixation (SPF), and structural or morselized bone grafting after total sacrectomy in patients were considered reconstruction-related factors. Cox regression models were used to analyze associations between postoperative fixation failure and risk factors for all models.

RESULTS

Postoperative fixation mechanical failure occurred in 25% of patients (16/63) who underwent total sacrectomy. Univariate analysis showed that the factors associated with spinopelvic fixation mechanical failure after total sacrectomy were the non-adoption of FRT of SPF and ASCF, the adoption of Type II sacroiliac resection, and female sex, whereas multivariate analysis demonstrated similar results, except for the adoption of Type II sacroilliac resection.

CONCLUSION

FRT connection of SPF and ASCF should be adopted in reconstruction after total sacrectomy, especially in female patients.

LEVEL OF EVIDENCE

3.

Clinical results and quality of life after reconstruction following sacrectomy for primary bone malignancy

BACKGROUND

Sacrectomy is a rare and demanding surgical procedure that results in major soft tissue defects and spinopelvic discontinuity. No consensus is available on the optimal reconstruction algorithm. Therefore, the present study evaluated the results of sacrectomy reconstruction and its impact on patients' quality of life (QOL).

METHODS

A retrospective chart review was conducted for 21 patients who underwent sacrectomy for a primary bone tumour. Patients were divided into groups based on the timing of reconstruction as follows: no reconstruction, immediate reconstruction or delayed reconstruction. QOL was measured using the EQ-5D instrument before and after surgery in patients treated in the intensive care unit.

RESULTS

The mean patient age was 57 (range 22-81) years. The most common reconstruction was gluteal muscle flap (n = 9) and gluteal fasciocutaneous flap (n = 4). Four patients required free-tissue transfer, three latissimus dorsi flaps and one vascular fibula bone transfer. No free flap losses were noted. The need for unplanned re-operations did not differ between groups (p = 0.397), and no significant differences were found for pre- and post-operative QOL or any of its dimensions.

DISCUSSION

Free flap surgery is reliable for reconstructing the largest sacrectomy defects. Even in the most complex cases, surgery can be safely staged, and final reconstruction can be carried out within 1 week of resection surgery without increasing peri‑operative complications. Sacrectomy does not have an immoderate effect on the measured QOL.

Sacral chordoma: clinical experience of a series of 11 patients over 18 years

Sacral chordoma are rare low-to-intermediate grade malignant tumours that occur most commonly within the sacrum. Sacrectomy with wide resection margins seems to offer the best long-term prognosis.  This study aims to review the management of sacral chordomas including the duration of symptoms, features, treatment, complications and local recurrence rate following surgery at a tertiary centre. We retrospectively reviewed 11 patients treated at our institution between years 1999 and 2015. Patient data included age, sex, history, radiographs, surgical details, onset of recurrence, subsequent treatment, disease-free survival and overall survival were analyzed. Nine patients underwent surgical management with 1 through a sacral approach and eight patients through a combined abdominosacral approach. Despite wide resection in our series, sacral chordoma poses a major problem with approximately 60% of patients having local recurrence in their follow-up.

En bloc resection of pelvic sarcomas with sacral invasion: a classification of surgical approaches and outcomes

Aims

The sacrum is frequently invaded by a pelvic tumour. The aim of this study was to review our experience of treating this group of patients and to identify the feasibility of a new surgical classification in the management of these tumours.

Patients and Methods

We reviewed 141 patients who, between 2005 and 2014, had undergone surgical excision of a pelvic tumour with invasion of the sacrum. In a new classification, pelvisacral (Ps) I, II, and III resections refer to a sagittal osteotomy through the ipsilateral wing of the sacrum, through the sacral midline, or lateral to the contralateral sacral foramina, respectively. A Ps a resection describes a pelvic osteotomy through the ilium and a Ps b resection describes a concurrent resection of the acetabulum with osteotomies performed through the pubis and ischium or the pubic symphysis. Within each type, surgical approaches were standardized to guide resection of the tumour.

Results

The mean operating time was 5.2 hours (sd 1.7) and the mean intraoperative blood loss was 1895 ml (sd 1070). Adequate margins were achieved in 112 (79.4%) of 141 patients. Nonetheless, 30 patients (21.3%) had local recurrence. The mean Musculoskeletal Tumor Society (MSTS93) lower-limb function score was 68% (sd 19; 17 to 100). According to the proposed classification, 92 patients (65%) underwent a Ps I resection, 33 patients (23%) a Ps II resection, and 16 (11%) patients a Ps III resection. Overall, 82 (58%) patients underwent a Ps a resection and 59 (42%) patient a Ps b resections. The new classification predicted surgical outcome.

Conclusion

We propose a comprehensive classification of surgical approaches for tumours of the pelvis with sacral invasion. Analysis showed that this classification helped in the surgical management of such patients and had predictive value for surgical outcomes. Cite this article: Bone Joint J 2018;100-B:798-805.

Rare case of a recurrent juvenile ossifying fibroma of the lumbosacral spine

Juvenile ossifying fibroma (JOF) is a rare benign bone tumor that occurs most frequently in the craniofacial bones of children and young adults. There are few case reports that describe its involvement outside the craniofacial skeleton, especially within the spinal column. While JOF is classified as a benign lesion, it may be locally aggressive and demonstrate a high propensity for recurrence, even after resection. Definitive surgical management may be challenging in naive cases, but it is particularly challenging in recurrent cases and when extensive spinal reconstruction is warranted. In this report, the authors describe the diagnosis and surgical management of a 29-year-old man who presented with a large recurrent sacral trabecular-subtype JOF. A review of literature regarding JOFs, management of recurrent primary spinal tumors, and sacral reconstruction are discussed.

[Development and current situation of reconstruction methods following total sacrectomy]

Objective

To review the development of the reconstruction methods following total sacrectomy, and to provide reference for finding a better reconstruction method following total sacrectomy.

Methods

The case reports and biomechanical and finite element studies of reconstruction following total sacrectomy at home and abroad were searched. Development and current situation were summarized.

Results

After developing for nearly 30 years, great progress has been made in the reconstruction concept and fixation techniques. The fixation methods can be summarized as the following three strategies: spinopelvic fixation (SPF), posterior pelvic ring fixation (PPRF), and anterior spinal column fixation (ASCF). SPF has undergone technical progress from intrapelvic rod and hook constructs to pedicle and iliac screw-rod systems. PPRF and ASCF could improve the stability of the reconstruction system.

Conclusion

Reconstruction following total sacrectomy remains a challenge. Reconstruction combining SPF, PPRF, and ASCF is the developmental direction to achieve mechanical stability. How to gain biological fixation to improve the long-term stability is an urgent problem to be solved.

Comprehensive biomechanical analysis of three reconstruction techniques following total sacrectomy: an in vitro human cadaveric model

OBJECTIVE

Aggressive sacral tumors often require en bloc resection and lumbopelvic reconstruction. Instrumentation failure and pseudarthrosis remain a clinical concern to be addressed. The objective in this study was to compare the biomechanical stability of 3 distinct techniques for sacral reconstruction in vitro.

METHODS

In a human cadaveric model study, 8 intact human lumbopelvic specimens (L2–pelvis) were tested for flexion-extension range of motion (ROM), lateral bending, and axial rotation with a custom-designed 6-df spine simulator as well as axial compression stiffness with the MTS 858 Bionix Test System. Biomechanical testing followed this sequence: 1) intact spine; 2) sacrectomy (no testing); 3) Model 1 (L3–5 transpedicular instrumentation plus spinal rods anchored to iliac screws); 4) Model 2 (addition of transiliac rod); and 5) Model 3 (removal of transiliac rod; addition of 2 spinal rods and 2 S-2 screws). Range of motion was measured at L4–5, L5–S1/cross-link, L5–right ilium, and L5–left ilium.

RESULTS

Flexion-extension ROM of the intact specimen at L4–5 (6.34° ± 2.57°) was significantly greater than in Model 1 (1.54° ± 0.94°), Model 2 (1.51° ± 1.01°), and Model 3 (0.72° ± 0.62°) (p < 0.001). Flexion-extension at both the L5–right ilium (2.95° ± 1.27°) and the L5–left ilium (2.87° ± 1.40°) for Model 3 was significantly less than the other 3 cohorts at the same level (p = 0.005 and p = 0.012, respectively). Compared with the intact condition, all 3 reconstruction groups statistically significantly decreased lateral bending ROM at all measured points. Axial rotation ROM at L4–5 for Model 1 (2.01° ± 1.39°), Model 2 (2.00° ± 1.52°), and Model 3 (1.15° ± 0.80°) was significantly lower than the intact condition (5.02° ± 2.90°) (p < 0.001). Moreover, axial rotation for the intact condition and Model 3 at L5–right ilium (2.64° ± 1.36° and 2.93° ± 1.68°, respectively) and L5–left ilium (2.58° ± 1.43° and 2.93° ± 1.71°, respectively) was significantly lower than for Model 1 and Model 2 at L5–right ilium (5.14° ± 2.48° and 4.95° ± 2.45°, respectively) (p = 0.036) and L5–left ilium (5.19° ± 2.34° and 4.99° ± 2.31°) (p = 0.022). Last, results of the axial compression testing at all measured points were not statistically different among reconstructions.

CONCLUSIONS

The addition of a transverse bar in Model 2 offered no biomechanical advantage. Although the implementation of 4 iliac screws and 4 rods conferred a definitive kinematic advantage in Model 3, that model was associated with significantly restricted lumbopelvic ROM.

Advances in surgical management for locally recurrent rectal cancer: How far have we come?

Locally recurrent rectal cancer (LRRC) is a complex disease with far-reaching implications for the patient. Until recently, research was limited regarding surgical techniques that can increase the ability to perform an en bloc resection with negative margins. This has changed in recent years and therefore outcomes for these patients have improved. Novel radical techniques and adjuncts allow for more radical resections thereby improving the chance of negative resection margins and outcomes. In the past contraindications to surgery included anterior involvement of the pubic bone, sacral invasions above the level of S2/S3 and lateral pelvic wall involvement. However, current data suggests that previously unresectable cases may now be feasible with novel techniques, surgical approaches and reconstructive surgery. The publications to date have only reported small patient pools with the research conducted by highly specialised units. Moreover, the short and long-term oncological outcomes are currently under review. Therefore although surgical options for LRRC have expanded significantly, one should balance the treatment choices available against the morbidity associated with the procedure and select the right patient for it.

What Are the Functional Outcomes After Total Sacrectomy Without Spinopelvic Reconstruction?

BACKGROUND

After total sacrectomy, many types of spinopelvic reconstruction have been described with good functional results. However, complications associated with reconstruction are not uncommon and usually result in further surgical interventions. Moreover, less is known about patient function after total sacrectomy without spinopelvic reconstruction, which may be indicated when malignant or aggressive benign bone and soft tissue tumors involved the entire sacrum.

QUESTIONS/PURPOSES

(1) What is the functional outcome and ambulatory status of patients after total sacrectomy without spinopelvic reconstruction? (2) What is the walking ability and ambulatory status of patients when categorized by the location of the iliosacral resection relative to the sacroiliac joint? (3) What complications and reoperations occur after this procedure?

METHODS

Between 2008 and 2014, we performed 16 total sacrectomies without spinopelvic reconstructions for nonmetastatic oncologic indications. All surviving patients had followup of at least 12 months, although two were lost to followup after that point (mean, 43 months; range, 12-66 months, among surviving patients). During this time period, we performed total sacrectomy without reconstruction for all patients with primary bone and soft tissue tumors (benign and malignant) involving the entire sacrum with no initial metastasis. The level of resection was the L5-S1 disc in 14 patients and L4-L5 disc in two patients. We classified the resection into two types based on the location of the iliosacral resection. Type I resections went medial to or through or lateral but close to the sacroiliac joint. Type II resections were far lateral (more than 3 cm from the posterior iliac spine) to the sacroiliac joint. Musculoskeletal Tumor Society (MSTS) scores, physical function assessments, and complications were gleaned from chart review performed by the treating surgeons (PK, BS). Video documentation of patients walking was obtained at followup in eight patients.

RESULTS

The mean overall MSTS scores was 17 (range, 5-27). Thirteen patients were able to walk, five without walking aids, two with a cane and sometimes without a walking aid, three with a cane, and three with a walker. Thirteen of 14 patients who had bilateral Type I resections or a Type I resection on one side and Type II on the contralateral side were able to walk, five without a walking aid, and had a mean MSTS score of 19 (range, 13-27). Two patients with bilateral Type II resection were only able to sit. Complications included wound dehiscences in 13 patients (which were treated with reoperation for drainage), sciatic nerve injury in seven patients, a torn ureter in one patient, and a rectal tear in one patient.

CONCLUSIONS

Without spinopelvic reconstruction, most patients in this series who underwent total sacrectomy were able to walk. Good MSTS scores could be expected in patients with bilateral Type I resections and patients with a Type I on one side and a Type II on the contralateral side. Total sacrectomy without spinopelvic reconstruction should be considered as a useful alternative to reconstructive surgery in patients who undergo Type I iliosacral resection on one or both sides.

LEVEL OF EVIDENCE

Level IV, therapeutic study.

Sacral Osteoneogenesis after Complete Sacrectomy in a Patient with Ewing Sarcoma

Ewing sarcomas are the second most common primary malignant bone tumors in childhood and adolescence which rapidly metastasize. Due to improvement of treatment options in recent years, the survival rate has significantly increased. Nevertheless, lethality is still high, and neurologic symptoms are frequent. To the best of our knowledge, this is the first reported case of a sacral osteoneogenesis after complete sacrectomy in a patient with Ewing sarcoma.