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.

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.

The Use of Anterior Lumbosacral Interbody Fusion in Spinopelvic Stabilization After High Partial Sacrectomy

BACKGROUND AND IMPORTANCE Traditionally, when a patient presents with a midline chordoma with extension to the mid-S1 body where neither S1 nerve roots can be spared, the recommendation would be to perform a total sacrectomy for en bloc resection. This procedure, however, results in a large bony defect that makes it difficult to achieve fusion across the lumbosacral and sacroiliac junction (SIJ). To help prevent this challenge in the situation described above, we propose performing a high sacrectomy for en bloc resection with placement of an anterior L5-S1 graft instead in specific situations where the tumor extends to the mid-S1 body leaving the superior aspect of S1 unaffected. CLINICAL PRESENTATION A 56-yr-old female presented to our clinic with back pain, leg pain, urinary incontinence, and perineal numbness. She was found to have a chordoma that extended to the mid-S1 body superiorly. Her S1 nerve roots were involved extraforaminally. We performed the operation described above with no signs of hardware malfunction or tumor recurrence at 5 mo. CONCLUSION In patients where the sacral tumor that involves the S1 nerve roots but does not involve the superior portion of the S1 body, there continues to be unaffected SIJ to allow for arthrodesis, and an anterior approach is necessary for other indications, we recommend performing a high partial sacrectomy with placement of an anterior L5-S1 graft rather than a total sacrectomy as long as the bony resection offers ability to obtain tumor margins.