Sacral tumor resection and the impact on pelvic incidence

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.

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.

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.

Can pelvic incidence change after spinal deformity correction to the pelvis with S2-alar-iliac screws?

PURPOSE

Pelvic incidence (PI) is assumed to be fixed, yet studies have reported PI changes after long fusions to the pelvis. In a cohort of ASD patients undergoing surgery with S2-alar-iliac (S2AI) screws, we sought to: (1) report the magnitude of PI changes, and (2) evaluate subsequent pelvic parameter changes.

METHODS

A retrospective case series of ASD patients undergoing surgical correction with S2AI screw placement and sagittal cantilever correction maneuvers was conducted. Patients were categorized based on preoperative PI: High-PI (H-PI) (PI ≥ 60°); Normal-PI (N-PI) (60° > PI > 40°); Low-PI (L-PI) (PI ≤ 40°). PI was measured preoperatively and immediately postoperatively. A significant PI change was established a priori at ≥ 6.0. PI, pelvic tilt (PT), lumbar lordosis (LL), and PI-LL mismatch were analyzed.

RESULTS

In 68 patients (82.3% female, ages 22-75 years), the average change in PI was 4.6° ± 3.1, and 25 (36.8%) had a PI change ≥ 6.0° with breakdown as follows: H-PI 12 (66.7%) patients, 9 (25.87%) patients, and 4 (33.3%) patients. Of 25 patients with PI changes, 10 (14.7%) had a PI increase and 15 (22.1%) had a PI decrease. Significant improvements were seen in PT, LL, PI-LL mismatch in all patients with a PI change ≥ 6.0°, in addition to both subgroups with an increase or decrease in PI.

CONCLUSIONS

PI changes of ≥ 6.0° occurred in 36.8% of patients, and H-PI patients most commonly experienced PI changes. Despite PI alterations, pelvic parameters significantly improved postoperatively. These results may be explained by sacroiliac joint laxity, S2AI screw placement, or aggressive sagittal cantilever techniques.

Comparison Between S2-Alar-Iliac Screw Fixation and Iliac Screw Fixation in Adult Deformity Surgery: Reoperation Rates and Spinopelvic Parameters

STUDY DESIGN

Retrospective cohort study.

OBJECTIVE

The S2-alar-iliac (S2AI) technique has been described as an alternative method for pelvic fixation in place of iliac screws (ISs) in spinal deformity surgery. The objective of this study was to analyze the impact of S2AI screws on radiographical outcomes, including spinopelvic parameters.

METHODS

A retrospective review of 17 patients receiving ISs and 46 patients receiving S2AI screws for correction of adult spinal deformity between 2010 and 2015 with minimum 1-year follow-up was conducted. Patient data on postoperative complications, including reoperation rates and proximal junctional kyphosis (PJK), and radiographical parameters was collected and statistically analyzed.

RESULTS

With mean follow-up of 21.1 months, the overall reoperation rate was significantly lower in the S2AI group than in the IS group (21.7% vs 58.8%, P = .01), but the incidence of PJK was similar (32.6% vs 35.3%, P > .99). Moreover, the time to reoperation in the IS group was significantly shorter than in the S2AI group (P = .001), and the S2AI group trended toward a longer time to reoperation due to PJK (P = .08). There was a significantly higher change in pelvic incidence (PI) in the S2AI group (-6.0°) compared with the IS group (P = .001).

CONCLUSIONS

Compared with the IS technique, the S2AI technique demonstrated a lower rate of overall reoperation, a similar rate of PJK, longer time to reoperation, and possible reduction in PI. Future studies may be warranted to clarify the mechanism of these results and how they can be translated into improved patient care.

Long-term follow-up and pregnancy after complete sacrectomy with lumbopelvic reconstruction: case report and literature review

BACKGROUND

Sacrectomy remains a technically complex procedure for resection of malignant pelvic neoplasia. Commonly, postoperative complications include permanent neurological deficits. Only a few studies have reported the long-term functional outcomes of patients who had undergone sacrectomy.

CASE PRESENTATION

We previously reported on the utilization of complete sacrectomy and lumbopelvic reconstruction for the management of primary myofibroblastic sarcoma of the sacrum and ilium in a 15-year-old female patient. In this report, we update her postoperative course with an additional 5 years of follow-up and Health-Related Quality of Life (HRQoL) outcomes. During this time period, she gave birth to two healthy full-term babies.

CONCLUSION

To the best of our knowledge, this is the first report of pregnancy after total sacrectomy and lumbopelvic reconstruction. We outline some of the challenges in the obstetrical management of this patient.

Robotic guidance for en bloc sacrectomy: a case report

STUDY DESIGN

Case report of a patient with primary osteosarcoma of the sacrum who underwent en bloc sacrectomy.

OBJECTIVE

To describe a novel approach using robotic guidance for sacral tumor resection.

SUMMARY OF BACKGROUND DATA

En bloc sacrectomy for aggressive primary malignancies or metastatic tumors of the sacrum can be technically challenging. Although imaging can delineate appropriately planned resection margins, the complex anatomy of the spinopelvic junction poses a challenge for the exact intraoperative execution of the preoperative plan.

METHODS

The patient was a 22-year-old male who was diagnosed with a primary sacral osteosarcoma. The mass extended to the left sacroiliac joint requiring a transiliac osteotomy. Preoperative robotic-guidance software was used allowing for virtual planning of the transiliac osteotomy.

RESULTS

During surgery, the robot was attached and synchronized with the preoperative imaging. Pilot holes were drilled along the planned iliac resection margin. With rigid tubes placed in the left iliac pilot holes, we passed a series of osteotomes parallel to the tubes to the same depth as our drillings and completed our left iliac osteotomy. Negative tumor margins were achieved and the postoperative course was uneventful.

CONCLUSION

We report the first case of robotic-guided en bloc transiliac resection of a primary sacral osteosarcoma with extension to the sacroiliac joint. Robotic guidance for tumor resection can be a useful tool in such challenging surgical procedures to fully resect the tumor, while minimizing disruption of the surrounding healthy anatomy.

LEVEL OF EVIDENCE

5.

Gait-simulating fatigue loading analysis and sagittal alignment failure of spinal pelvic reconstruction after total sacrectomy: comparison of 3 techniques

OBJECT

Reconstruction after total sacrectomy is a critical component of malignant sacral tumor resection, permitting early mobilization and maintenance of spinal pelvic alignment. However, implant loosening, graft migration, and instrumentation breakage remain major problems. Traditional techniques have used interiliac femoral allograft, but more modern methods have used fibular or cage struts from the ilium to the L-5 endplate or sacral body replacement with transiliac bars anchored to cages to the L-5 endplate. This study compares the biomechanical stability under gait-simulating fatigue loading of the 3 current methods.

METHODS

Total sacrectomy was performed and reconstruction was completed using 3 different constructs in conjunction with posterior spinal screw rod instrumentation from L-3 to pelvis: interiliac femur strut allograft (FSA); L5-iliac cage struts (CSs); and S-1 body replacement expandable cage (EC). Intact lumbar specimens (L3-sacrum) were tested for flexion-extension range of motion (FE-ROM), axial rotation ROM (AX-ROM), and lateral bending ROM (LB-ROM). Each instrumented specimen was compared with its matched intact specimen to generate an ROM ratio. Fatigue testing in compression and flexion was performed using a custom-designed long fusion gait model.

RESULTS

Compared with intact specimen, the FSA FE-ROM ratio was 1.22 ± 0.60, the CS FE-ROM ratio was significantly lower (0.37 ± 0.12, p < 0.001), and EC was lower still (0.29 ± 0.14, p < 0.001; values are expressed as the mean ± SD). The difference between CS and EC in FE-ROM ratio was not significant (p = 0.83). There were no differences in AX-ROM or LB-ROM ratios (p = 0.77 and 0.44, respectively). No failures were noted on fatigue testing of any EC construct (250,000 cycles). This was significantly improved compared with FSA (856 cycles, p < 0.001) and CS (794 cycles, p < 0.001).

CONCLUSIONS

The CS and EC appear to be significantly more stable constructs compared with FSA with FE-ROM. The 3 constructs appear to be equal with AX-ROM and LB-ROM. Most importantly, EC appears to be significantly more resistant to fatigue compared with FSA and CS. Reconstruction of the load transfer mechanism to the pelvis via the L-5 endplate appears to be important in maintenance of alignment after total sacrectomy reconstruction.

Preservation of the contralateral sacral nerves during hemisacrectomy for sacral malignancies

PURPOSE

This study aimed to evaluate the oncologic and functional outcome of the cases treated with hemisacrectomy through a sagittal plane in the sacrum and simultaneous en bloc resection together with the ipsilateral sacroiliac joint without sacrificing the contralateral sacral nerves and summarize tumor resection techniques and reconstruction strategy.

METHODS

En bloc resection of a sacral malignancy with ipsilateral sacroiliac joint and preservation of the contralateral sacral nerves by sagittal hemisacrectomy had been performed in 15 patients. An intra-abdominal aortic balloon was used in all these cases and a combined posterior-anterior approach was adopted. A modified Galveston technique was used to reestablish spinopelvic stability and a nonvascularized fibula autograft was used in selected cases.

RESULTS

Contralateral sacral nerves were preserved in all 15 patients. Adequate margins (wide and marginal margin) were accomplished in 10 patients. Local recurrence occurred in seven (47%) patients, and four of these had an inadequate margin. There was no perioperative death. Four (27%) patients had wound problems. No mechanical breakdown occurred until the last follow-up. All the patients were able to walk without the use of a walking aid. Sphincter function was partially preserved in all these patients. At the last follow-up, seven (47%) patients survived without evidence of disease, two (13%) patients lived with disease, and six (40%) patients had died of disease.

CONCLUSIONS

This procedure has an oncologic outcome that is similar to that of other high sacrectomy and a much better function outcome. Although demanding, it is indicated in selected patients.

En bloc resection of sacral chordomas aided by frameless stereotactic image guidance: a technical note

BACKGROUND

The most important predictor of survival for patients with sacral chordomas is an initial en bloc resection with negative margins. However, obtaining negative margins can be technically challenging. Intraoperative navigation may be helpful in attempting an excision with negative margins.

OBJECTIVE

This is the first report of partial sacrectomy guided by frameless stereotactic navigation.

METHODS

Three patients with a mean age of 58.7 years underwent en bloc resection of sacral chordomas aided by image guidance. Intraoperatively, the reference arc was clamped to the spinous process of L5 and the bony landmarks of S1 were used for registration. Subsequently, the drill was registered, allowing the osteotomy trajectory to be visualized in real time with reference to the patients' anatomy and tumor location.

RESULTS

None of the patients had any intraoperative or postoperative complications. Two patients with smaller tumors (5 cm) had negative margins, whereas the third patient with an 11.5 cm tumor had marginal margins. With an average follow-up of 44 months, none of the patients have had a recurrence of the tumor.

CONCLUSION

The use of frameless stereotaxy during the en bloc resection of sacral tumors is safe and feasible. Frameless stereotactic navigation was a useful adjunct to preoperative imaging and to the surgeon's anatomic knowledge. Image guidance was used during the osteotomies to decrease the likelihood of injury to vital adjacent structures or violation of the tumor capsule and to increase the likelihood that the appropriate surrounding tissue was resected to attempt a wide or marginal resection.