Resection of giant invasive sacral schwannoma using image-based customized osteotomy tools

Rare retroperitoneal giant sacral schwannoma: A case report

Schwannomas localized in the sacrum are relatively infrequent, accounting for 1-5% of all spinal axis schwannomas; they present with vague symptoms or are symptomless, so often grow to a considerable size before detection. Sacral schwannomas occasionally present with enormous dimensions, and these tumors are termed giant sacral schwannomas. However, their surgical removal is challenging owing to an abundant vascularity. The present study retrospectively analyzed the clinical and follow-up data of a patient with a giant sacral schwannoma. The patient experienced numbness in the left buttock and lower extremity, with radiating pain in the sole of the foot that had persisted for 3 years. A presacral mass was found by computed tomography examination 6 months after the stool had become thin. A tumor resection was performed using the anterior abdominal approach. A schwannoma was diagnosed by postoperative pathology. The postoperative course was uneventful, with the complete resolution of symptoms during the 21-month clinical follow-up. Overall, the present study reports the case of a giant sacral schwannoma with pelvic pain that was resected without complications and also discusses its successful management. Additionally, the study presents a systematic review of the literature. We consider that the surgical treatment of giant sacral schwannomas with piecemeal subtotal excision can achieve good outcomes, avoiding unnecessary neurological deficits.

[Clinical application of three-dimensional printed osteotomy guide plate and personalized prosthesis in knee-preserving tumor resection]

OBJECTIVE

To investigate the mid-term effectiveness of three-dimensional (3D) printed osteotomy guide plate and personalized prosthesis in knee-preserving tumor resection.

METHODS

The clinical data of 12 patients who underwent knee-preserving tumor resection and reconstruction with 3D printed osteotomy guide plate and personalized prosthesis between September 2016 and October 2018 were retrospectively analyzed. There were 7 males and 5 females. The age ranged from 7 to 59 years, with a median of 44.5 years. There were 11 cases of osteosarcoma and 1 case of fibrosarcoma, all of which were Enneking grade ⅡB. The distance from the tumor to the joint surface was 5.5-8.2 cm, with an average of 6.94 cm. Incision healing, tumor recurrence, periprosthetic fracture, and aseptic loosening were observed after operation. The Musculoskeletal Tumor Society (MSTS) scoring system was used to evaluate the function of the patients, and the knee flexion range of motion was measured.

RESULTS

The 12 patients were followed up 41-66 months, with an average of 54.5 months. The length of osteotomy ranged from 14 to 26 cm, with an average of 22.08 cm. Except for 2 patients with superficial infection of incision tissue, no deep infection involving the prosthesis occurred, no patient underwent revision surgery because of prosthesis infection. During the follow-up, local recurrence occurred in 2 cases and distant metastasis occurred in 3 cases. The overall disease-free survival rate was 58.3%. Two patients died of lung metastasis, and the overall survival rate was 83.3%. One patient underwent amputation due to local recurrence, and 1 patient underwent total knee arthroplasty due to prosthesis rupture. No aseptic loosening of the prosthesis and periprosthetic fracture occurred during the follow-up, and the overall prosthesis survival rate was 83.3%. At last follow-up, 10 patients obtained satisfactory knee flexion range of motion that ranged from 95° to 125°, with an average of 110°. Two children could not cooperate with early rehabilitation treatment due to pain, and the knee flexion range of motion was not ideal (50°, 75°). All patients achieved acceptable lower limb function with MSTS scores ranged from 26 to 30, with an average of 28. All patients walked without crutches.

CONCLUSION

The treatment of malignant bone tumors around the knee joint with 3D printed osteotomy guide plate and personalized prosthesis can preserve the articular surface, obtain good limb function, reduce the risk of aseptic loosening of prosthesis, and achieve better mid-term effectiveness.

Surgical management of sacral schwannomas: a 21-year mayo clinic experience and comparative literature analysis

INTRODUCTION

Sacral and presacral schwannomas are rare, accounting for a minority of spinal schwannomas. We present our institution's experience surgically treating spinal schwannomas and compare it to the literature.

METHODS

Data were collected for 27 patients treated surgically for sacral or presacral schwannoma between 1997 and 2018 at all Mayo Clinic locations and 93 patients in the literature. Kaplan-Meier disease-free survival analysis was conducted. Unpaired two-sample t tests and Fisher's exact tests assessed statistical significance between groups.

RESULTS

Our patients and those in the literature experienced a similar age at diagnosis (49.9 y/o. vs 43.4 y/o., respectively). Most of our patients (59.3%) reported full recovery from symptoms, while a minority reported partial recovery (33.3%) and no recovery (11.1%). A smaller percentage in the literature experienced full recovery (31.9%) and partial recovery (29.8%) but also no recovery (1.1%). Our patients experienced fewer complications (14.8% versus 25.5%). Disease-free survival curves for all patients showed no significant variation in progression by extent of resection of schwannoma (log-rank P = 0.26). No lesion progression was associated with full or partial symptom improvement (p = 0.044), and female patients were more likely to undergo resection via a posterior approach (p = 0.042).

CONCLUSION

Outcomes of patients with sacral or presacral schwannomas vary based on patient demographics, tumor characteristics, symptoms, and surgical treatment. Among the range of symptoms experienced by these patients, the most common is pain. Prognosis improves and overall survival is high when the surgical approach towards sacral schwannomas is prepared and executed appropriately.

Clinical applications and prospects of 3D printing guide templates in orthopaedics

Background

With increasing requirements for medical effects, and huge differences among individuals, traditional surgical instruments are difficult to meet the patients' growing medical demands. 3D printing is increasingly mature, which connects to medical services critically as well. The patient specific surgical guide plate provides the condition for precision medicine in orthopaedics.

Methods

In this paper, a systematic review of the orthopedic guide template is presented, where the history of 3D-printing-guided technology, the process of guides, and basic clinical applications of orthopedic guide templates are described. Finally, the limitations of the template and possible future directions are discussed.

Results

The technology of 3D printing surgical templates is increasingly mature, standard, and intelligent. With the help of guide templates, the surgeon can easily determine the direction and depth of the screw path, and choose the angle and range of osteotomy, increasing the precision, safety, and reliability of the procedure in various types of surgeries. It simplifies the difficult surgical steps and accelerates the growth of young and mid-career physicians. But some problems such as cost, materials, and equipment limit its development.

Conclusions

In different fields of orthopedics, the use of guide templates can significantly improve surgical accuracy, shorten the surgical time, and reduce intraoperative bleeding and radiation. With the development of 3D printing, the guide template will be standardized and simplified from design to production and use. 3D printing guides will be further sublimated in the application of orthopedics and better serve the patients.

The translational potential of this paper

Precision, intelligence, and individuation are the future development direction of orthopedics. It is more and more popular as the price of printers falls and materials are developed. In addition, the technology of meta-universe, digital twin, and artificial intelligence have made revolutionary effects on template guides. We aim to summarize recent developments and applications of 3D printing guide templates for engineers and surgeons to develop more accurate and efficient templates.

Novel Applications of Spinal Navigation in Deformity and Oncology Surgery-Beyond Screw Placement

Computer-assisted navigation has made a major impact on spine surgery, providing surgeons with technological tools to safely place instrumentation anywhere in the spinal column. With advances in intraoperative image acquisition, registration, and processing, many surgeons are now using navigation in their practices. The incorporation of navigation into the workflow of surgeons continues to expand with the evolution of minimally invasive techniques and robotic surgery. While numerous investigators have demonstrated the benefit of navigation for improving the accuracy of instrumentation, few have reported applying this technology to other aspects of spine surgery. Surgeries to correct spinal deformities and resect spinal tumors are technically demanding, incorporating a wide range of techniques not only for instrumentation placement but also for osteotomy planning and executing the goals of surgery. Although these subspecialties vary in their objectives, they share similar challenges with potentially high complications, invasiveness, and consequences of failed execution. Herein, we highlight the utility of using spinal navigation for applications beyond screw placement: specifically, for planning and executing osteotomies and guiding the extent of tumor resection. A narrative review of the work that has been done is supplemented with illustrative cases demonstrating these applications.

Three-dimensional printing-based personalized limb salvage and reconstruction treatment of pelvic tumors

BACKGROUND AND OBJECTIVES

The treatment of pelvic tumors is widely recognized to be challenging. The purpose of this study was to evaluate the efficacy of personalized three-dimensional (3D) printing-based limb salvage and reconstruction treatment for pelvic tumors.

METHODS

Twenty-eight pelvic tumor patients were enrolled. 3D printing lesion models and osteotomy templates were prepared for surgery planning, prosthesis design, and osteotomy assistance during surgery. 3D printing-based personalized pelvic prostheses were manufactured and used in all 28 patients. Follow-up of postoperative survival, prosthesis survival, imaging examinations, and Musculoskeletal Tumor Society (MSTS) lower limb functional scores were carried out.

RESULTS

The mean follow-up period was 32.2 months, during which 16 patients had disease-free survival, 3 survived with the disease, and 9 died. The prostheses were stable, and the mean offset of the center of rotation was 5.48 mm. The prosthesis-bone interface showed good integration. For the 19 surviving patients, the mean MSTS lower limb functional score was 23.2. Postoperative complications included superficial infection in six patients and hip dislocation in three patients.

CONCLUSIONS

Personalized 3D printing-based limb salvage and reconstruction was an effective treatment for pelvic tumors. Our patients achieved good early postoperative efficacy and functional recovery.

Complex Bone Tumors of the Trunk-The Role of 3D Printing and Navigation in Tumor Orthopedics: A Case Series and Review of the Literature

The combination of 3D printing and navigation promises improvements in surgical procedures and outcomes for complex bone tumor resection of the trunk, but its features have rarely been described in the literature. Five patients with trunk tumors were surgically treated in our institution using a combination of 3D printing and navigation. The main process includes segmentation, virtual modeling and build preparation, as well as quality assessment. Tumor resection was performed with navigated instruments. Preoperative planning supported clear margin multiplanar resections with intraoperatively adaptable real-time visualization of navigated instruments. The follow-up ranged from 2–15 months with a good functional result. The present results and the review of the current literature reflect the trend and the diverse applications of 3D printing in the medical field. 3D printing at hospital sites is often not standardized, but regulatory aspects may serve as disincentives. However, 3D printing has an increasing impact on precision medicine, and we are convinced that our process represents a valuable contribution in the context of patient-centered individual care.

Management of giant presacral schwannoma. Clinical series and literature review

PURPOSE

Presacral schwannomas are rare tumors. Due to their benign nature and slow growth, these tumors are often giant and become difficult to treat. Their removal is a surgical challenge with different strategies reported in the literature. This study presents the consecutives cases of presacral schwannomas operated on in our institution, our surgical strategy and literature review.

METHODS

This retrospective study includes all consecutive patients operated on for a pre-sacral schwannoma in our department between 2006 and 2019, i.e. 6 patients. We report clinical features, pre and post-operative imaging, surgical data and post-operative outcomes.

RESULTS

All patients had symptoms before surgery (constipation, dysuria, radicular or lower back pain) with an average duration of 7.4 months. All patients underwent an MRI and a CT scan before the surgery. Five patients had type III schwannoma according to Klimo classification and one patient had a type II. The average size was 504,9 cm³ (range 53,1-1495,4). All the patients were operated on by an anterior approach in a double team with an mean duration of 246 min. Intraoperative bleeding was less than 500 ml for 4 patients, 2 patients had significant bleeding (2700 and 2900 mL). Excision was total or subtotal in all cases. One patient had an intraoperative complication (air embolism). Follow up at 3 months was excellent with a disappearance of symptoms for all patients except one patient who retained constipation. One patient had a late complication (bowel obstruction due to tissue adhesions). At last follow-up after phone interview, no patient had clinical symptoms that could suggest a recurrence.

CONCLUSION

The anterior approach with a double surgical team is a great option for the treatment of presacral schwannoma. Combined with adequate preoperative imaging and intraoperative stimulation, it reduces the risk of intra and postoperative complications.

Three-dimensional-printed intercalary prosthesis for the reconstruction of large bone defect after joint-preserving tumor resection

BACKGROUND

Joint-preserving intercalary tumor resection can result in better proprioception and a more normal joint function after reconstruction. However, most reported reconstruction techniques are usually associated with frequent complications. Therefore, the approach of reconstruction following joint-preserving tumor resection warrants further study.

METHODS

Between September 2016 and October 2018, 12 patients with metaphyseal malignant bone tumors around the knee joint were treated by joint-preserving intercalary resections with the aid of three-dimensional (3D)-printed osteotomy guide plates and reconstructions using 3D-printed intercalary prostheses. We assessed the accuracy of the resection by comparing the cross sections at the resection plane with 3D-printed matching surface of the prostheses. The functional outcomes, complications and oncological status were also evaluated.

RESULTS

All patients were observed for 7 to 32 months with an average follow-up of 22.5 months. The achieved resection was accurate, with accurate matching between the residual bone and prosthesis. The mean MSTS score was 28 (range, 26-30). Superficial infection occurred in two patients. Local recurrence was observed in one patient, while pulmonary metastasis was identified in one patient.

CONCLUSIONS

The personalized osteotomy guide plate and prosthesis based on 3D printing technique facilitate joint-preserving tumor resection and functional reconstruction. However, longer follow-up and larger sample size are required to clarify its long-term outcomes.

LEVEL OF EVIDENCE

Level IV, therapeutic study.

Surgical management of giant presacral schwannoma: systematic review of published cases and meta-analysis

OBJECTIVE

Giant presacral schwannomas are rare sacral tumors found in less than 1 of every 40,000 hospitalizations. Current management of these tumors is based solely upon case reports and small case series. In this paper the authors report the results of a systematic review of the available English literature on presacral schwannoma, focused on identifying the influence of tumor size, tumor morphology, surgical approach, and extent of resection (EOR) on recurrence-free survival and postoperative complications.

METHODS

The medical literature (PubMed and EMBASE) was queried for reports of surgically managed sacral schwannoma, either involving 2 or more contiguous vertebral levels or with a diameter ≥ 5 cm. Tumor size and morphology, surgical approach, EOR, intraoperative and postoperative complications, and survival data were recorded.

RESULTS

Seventy-six articles were included, covering 123 unique patients (mean age 44.1 ± 1.4 years, 50.4% male). The most common presenting symptoms were leg pain (28.7%), lower back pain (21.3%), and constipation (15.7%). Most surgeries used an open anterior-only (40.0%) or posterior-only (30%) approach. Postoperative complications occurred in 25.6% of patients and local recurrence was noted in 5.4%. En bloc resection significantly improved progression-free survival relative to subtotal resection (p = 0.03). No difference existed between en bloc and gross-total resection (GTR; p = 0.25) or among the surgical approaches (p = 0.66). Postoperative complications were more common following anterior versus posterior approaches (p = 0.04). Surgical blood loss was significantly correlated with operative duration and tumor volume on multiple linear regression (both p < 0.001).

CONCLUSIONS

Presacral schwannoma can reasonably be treated with either en bloc or piecemeal GTR. The approach should be dictated by lesion morphology, and recurrence is infrequent. Anterior approaches may increase the risk of postoperative complications.

Giant Presacral Schwannoma in Man: Report of a Case with Emphasis on Imaging Findings

BACKGROUND

Schwannoma is a tumor arising from peripheral nerve sheaths and commonly occurs in the head, neck, and upper and lower extremities. Schwannoma in the presacral space is relatively rare and is often misdiagnosed before pathologic diagnosis is made.

CASE DESCRIPTION

Here we discuss a case of giant presacral schwannoma in a 34-year-old man with an emphasis on imaging findings.

CONCLUSIONS

Solid and encapsulated, round or oval, with rich blood supply may be the characteristic imaging findings of presacral schwannoma, which may narrow the differential diagnosis of hypervascular pelvic lesions.

Radiological Society of North America (RSNA) 3D printing Special Interest Group (SIG): guidelines for medical 3D printing and appropriateness for clinical scenarios

Medical three-dimensional (3D) printing has expanded dramatically over the past three decades with growth in both facility adoption and the variety of medical applications. Consideration for each step required to create accurate 3D printed models from medical imaging data impacts patient care and management. In this paper, a writing group representing the Radiological Society of North America Special Interest Group on 3D Printing (SIG) provides recommendations that have been vetted and voted on by the SIG active membership. This body of work includes appropriate clinical use of anatomic models 3D printed for diagnostic use in the care of patients with specific medical conditions. The recommendations provide guidance for approaches and tools in medical 3D printing, from image acquisition, segmentation of the desired anatomy intended for 3D printing, creation of a 3D-printable model, and post-processing of 3D printed anatomic models for patient care.

The extended posterior approach for resection of sacral tumours

PURPOSE

The conventional posterior approach is mostly advocated for excision of sacral tumours below S2. We describe an operative technique of single-stage en bloc resection of sacral tumours, extending up to S1, through an extended posterior approach.

METHOD

Nine patients, who had undergone resection of sacral tumours, by the described technique formed the basis of this study. Four patients had chordomas, whereas schwannoma, neurilemmoma, giant-cell tumour, malignant paraganglioma and recurrent Ewing's sarcoma were seen in one patient each. They were followed up at regular intervals with a mean follow-up of 45.4 months. Perioperative complications, their functional and oncological outcomes at final follow-up were analysed.

RESULT

None of the patients had any perioperative complications like uncontrolled haemorrhage, injury to the rectum, deep vein thrombosis or pulmonary embolism. One patient had a superficial wound infection which subsided with regular dressing, and another patient developed a wound breakdown that required an additional flap procedure. At final follow-up, six patients were able to walk without any assistive devices, six patients had normal bladder function, and five patients had normal bowel function. Five patients did not have any recurrence at final follow-up, whereas two were alive with the disease and two had died.

CONCLUSION

The reported technique allows en bloc resection of sacral tumours up to S1, through a posterior-only approach. It is less invasive with minimal morbidity. The functional and oncological outcomes are similar to those reported by other investigators. These slides can be retrieved from electronic supplementary material.

Three-dimensional Technologies in Orthopedics

New 3-dimensional digital technologies are revolutionizing orthopedic clinical practice, allowing structures of any complexity to be manufactured in just hours. Such technologies can make surgery for complex cases more precise, more cost-effective, and possibly easier to perform. Applications include pre-operative planning, surgical simulation, patient-specific instrumentation and implants, bioprinting, prosthetics, and orthotics. The basic principles of 3- dimensional technologies, including imaging, design, numerical simulation, and printing, and their current applications in orthopedics are reviewed. [Orthopedics. 2018; 41(1):12-20.].

Virtual Preoperative Simulation for Excision of Spinal Tumors: Surgeon Processing of Medical Computer-Assisted Design Software

As medical computer-aided design (CAD) has improved, virtual 3-dimensional medical images have been gaining more easily without any special practice. These images can be applied to various clinical fields. This article illustrates virtual preoperative simulation for excision of spinal tumors using medical CAD software. The software was used directly by the surgeon. The process of virtual preoperative simulation for spinal tumor surgery was found to be not inordinately complicated. And, virtual simulation was helpful in determining surgical steps as well as understanding the surgical anatomy.

Systematic review of 3D printing in spinal surgery: the current state of play

Three-dimensional printing (3DP), also known as "Additive Manufacturing", is a rapidly growing industry, particularly in the area of spinal surgery. Given the complex anatomy of the spine and delicate nature of surrounding structures, 3DP has the potential to aid surgical planning and procedural accuracy. We perform a systematic review of current literature on the applications of 3DP in spinal surgery. Six electronic databases were searched for original published studies reporting cases or outcomes for 3DP surgical models, guides or implants for spinal surgery. The findings of these studies were synthesized and summarized. These searches returned a combined 2,411 articles. Of these, 54 were included in this review. 3DP is currently used for surgical planning, intra-operative surgical guides, customised prostheses as well as "Off-the-Shelf" implants. The technology has the potential for enhanced implant properties, as well as decreased surgical time and better patient outcomes. The majority of the data thus far is from low-quality studies with inherent biases linked with the excitement of a new field. As the body of literature continues to expand, larger scale studies to evaluate advantages and disadvantages, and longer-term follow up will enhance our knowledge of the effect 3DP has in spinal surgery. In addition, issues such as financial impact, time to design and print, materials selection and bio-printing will evolve as this rapidly expanding field matures.