Lumbopelvic reconstruction after combined L5 spondylectomy and total sacrectomy for en bloc resection of a malignant fibrous histiocytoma

Lumbar functional evaluation of pelvic bone sarcomas after surgical resection and spinal pelvic fixation: A clinical study of 304 cases

AIMS

We endeavored to introduce a novel scoring system (Lumbar Functional Index, LFI) capable of evaluating lumbar function in pelvic bone sarcoma patients who underwent surgical resection and spinal pelvic fixation, while simultaneously identifying the incidence, outcomes, and risk factors of lumbar function impairment among these populations.

PATIENTS AND METHODS

A cohort of 304 primary bone sarcoma patients were recruited. The LFI was created based on the Oswestry Dysfunction Index (ODI) and Japanese Orthopaedic Association (JOA) scores. Lumbar function impairment was defined as LFI score ≥ 18 points, which was identified as high LFI. Demographic data, clinical characteristics, and oncological outcomes were analyzed.

RESULTS

The cohort included chondrosarcoma (39.8%), osteosarcoma (29.9%), Ewing sarcoma (8.6%), bone-derived undifferentiated pleomorphic sarcoma (7.2%), giant cell tumor of bone (7.2%), chordoma (2.3%), and other bone sarcomas (5.0%). The LFI score exhibited significant negative correlation with common scoring systems of bone sarcoma. The incidence of high LFI was 23.0%. Patients with high LFI demonstrated a higher prevalence of type I + II + III + IV pelvic tumor, more sacrificed nerve roots and bilateral lumbar spine fixation during surgery, while lower percentage of R0 resection and local control of pelvic tumor. Decreased median overall survival (30 vs. 52 months, p < 0.001) and recurrence-free survival (14 vs. 24 months, p < 0.001) time were observed in these patients. Type I + II + III + IV pelvic tumor and sacrificed nerve roots≥2 were identified as risk factors for high LFI, while R0 resection and local control were identified as protective factors.

CONCLUSION

The LFI scoring system exhibited a significant negative correlation to current scoring systems. High LFI patients had worse prognosis and distinct characteristics. The risk factors of high LFI included type I + II + III + IV pelvic tumor and sacrificed nerve roots≥2, and the protective factors included R0 resection and local control.

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.

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.

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.

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.

[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.

A Major Response to Trabectedin in Metastatic Malignant Fibrous Histiocytoma of the Vertebra: A Case Report and Review of the Literature

Malignant fibrous histiocytoma is an aggressive tumor, the most common soft-tissue sarcoma of adult age. It is usually located in the extremities and retroperitoneum, and very rarely there is skeletal involvement. Surgery is the preferred treatment in early disease; in advanced disease, chemotherapy is the main therapeutic strategy. We present a 25-year-old female patient diagnosed with a vertebral mass in T5 with a severely compromised spinal cord. She underwent surgical decompression and the pathological findings were consistent with malignant fibrous histiocytoma. After several surgical treatments she had pulmonary progression and was therefore started on chemotherapy. She had a very poor response to most of the administered regimens until she initiated trabectedin 1 mg/m2 every three weeks. She showed a significant improvement with a major response of the lung metastases. This report indicates that trabectedin is an active drug in advanced, previously treated metastatic malignant fibrous histiocytoma.

Surgical approach selection for total spondylectomy for the treatment of giant cell tumors in the lumbar spine: A retrospective analysis of 12 patients from a single center

AIM

To describe the selection of the surgical approach used for total spondylectomy in the treatment of giant cell tumors of the lumbar spine.

METHODS

This retrospective study included 12 patients with giant cell tumors of the lumbar spine who underwent total spondylectomy. The effect of the Weinstein-Boriani-Biagini surgical staging and tumor location on the approach selected was evaluated.

RESULTS

Two tumors were treated using the posterior approach: one located in L1, extending into layers A∼D and involving sectors 2∼6, and the other located in L4, extending into layers B∼D and involving sectors 4∼11. Four tumors (one each located in L1, L2, L3, and L4) were treated by a combined posterior and anterolateral approach as the tumors involved sectors 5∼6 or 7∼8. Six tumors were treated using a combined posterior and anterior approach, two tumors located in L4, extending into layers A∼D and involving sectors 1∼12, and associated with a soft tissue mass extending into layer A and involving sectors 5∼8; and four tumors located in L5. Complications were observed in 9 of the 12 patients.

CONCLUSIONS

A posterior approach is the obvious strategy for tumors located in L1∼L4 and extending into layers B∼D or A and involving sectors 1∼3 or 10∼12. For tumors invading beyond layer A and involving sectors 1∼12, including those with a soft tissue mass extending from layer A, with involvement of sectors 4∼9, a posterior approach combined with an anterolateral or anterior approach is required. For L5 tumors, a combined posterior and anterior approach is needed.

L5 corpectomy-the lumbosacral segmental geometry and clinical outcome-a consecutive series of 14 patients and review of the literature

PURPOSE

We analyzed the lumbosacral segmental geometry and clinical outcome in patients undergoing L5 corpectomy.

METHODS

Fourteen consecutive patients who underwent L5 (n = 12) or L4 + 5 (n = 2) corpectomy at our department between January 2010 and April 2015 were included. All patients underwent a baseline physical and neurologic examination on admission. The diagnostic routine included MRI and CT scans and, if possible, an upright X-ray of the lumbar spine before and after surgery. The local lordosis angle [L4(L3)-S1] was measured.

RESULTS

The most common pathology was infection (N = 7), followed by neoplastic disease (n = 3), pseudarthrosis (n = 2) after previous spinal fusion procedures and burst fractures (n = 2) of the L5 vertebral body. We observed seven complications (2 intraoperative; 5 postoperative) in five (36%) patients. Three patients needed revision surgery because of cage subsidence and/or dislodgement (21%). Additional anterior plating was used in two of the revision surgeries to secure the cage. Two spondylodiscitis patients (14%) with complications died of sepsis. Of the 12 remaining patients, 8 were available for follow-up.

CONCLUSION

L5 corpectomy is a technically challenging but feasible procedure even though the overall complication rate can be as high as 36%. The radiologic and clinical outcome seems to be better in patients with a small lordosis angle between L4(L3) and S1, since an angle of >50 degrees seems to facilitate cage dislodgement. Anterior plating should be considered in these cases to prevent implant failure.

One-step reconstruction with a 3D-printed, custom-made prosthesis after total en bloc sacrectomy: a technical note

BACKGROUND

Surgeries for primary malignancies involving upper sacrum require total en bloc sacrectomy followed by complex mechanical reconstruction, which might be simplified by application of the three-dimensional (3D) printing technique.

PURPOSES

To describe the design of a 3D-printed custom-made prosthesis for reconstruction after total en bloc sacrectomy, the surgical technique, and the clinical and functional outcome of a patient.

METHODS

A 62-year-old patient with recurrent sacral chordoma was admitted in our center. One-stage total en bloc sacrectomy through posterior approach was planned, and a 3D-printed sacral prosthesis was prepared for reconstruction according to the anticipated osteotomic planes.

RESULTS

The patient received one-stage total en bloc sacrectomy through posterior approach followed by reconstruction with the 3D-printed sacral prosthesis. The whole procedure took 5 h, and intra-operative blood loss was 3400 ml. The patient recovered uneventfully and started ambulation at 3 weeks after surgery. An asymptomatic instrument failure was found radiographically at 8-month follow-up. At 1 year after surgery, the patient was disease free and could walk over short distance with crutches without pain or any mechanical instability.

CONCLUSIONS

The advantages of our reconstruction method included: (1) the prosthesis provided an optimal reconstruction of lumbosacral and pelvic ring by integrating spinal pelvic fixation, posterior pelvic ring fixation, and anterior spinal column fixation in one step and (2) its porous surface could induce bone ingrowth and might enhance stability. Although there was an instrumental failure, we considered that it could be one reconstructive option. More research is warranted focusing on the modification of locations, diameters, and quantity of screws and biomechanical characteristics. The long-term functional and bone in-growth outcome will be followed to validate the use of the prosthesis.

Pelvic reconstruction after subtotal sacrectomy for sacral chondrosarcoma using cadaveric and vascularized fibula autograft: Technical note

A novel method of spinopelvic ring reconstruction after partial sacrectomy for a chondrosarcoma is described. Chondrosarcoma is one of the most common primary malignant bone tumors, and en bloc resection is the mainstay of treatment. Involvement of the pelvis as well as the sacrum and lumbar spine can result in a technically difficult challenge for en bloc resection and for achievement of appropriate load-bearing reconstruction. After en bloc resection in their patient, the authors achieved reconstruction with a rod and screw construct including vascularized fibula graft as the main strut from the lumbar spine to the pelvis. Additionally, a cadaveric allograft strut was used as an adjunct for the pelvic ring. This is similar to a modified Galveston technique with vascularized fibula in place of the Galveston rods. The vascularized fibula provided appropriate biomechanical support, allowing the patient to return to independent ambulation. There was no tumor recurrence; neurological status remained stable; and the allograft construct integrated well and even increased in size on CT scans and radiographs in the course of a follow-up longer than 7 years.

Imaging appearances and clinical outcome following sacrectomy and ilio-lumbar reconstruction for sacral neoplasia

OBJECTIVE

Sacrectomy and ilio-lumbar reconstruction is an uncommonly performed complex surgical procedure for the treatment of sacral neoplasia. There are many challenges in the post-operative period including the potential for tumor recurrence, infection, and construct failure. We present our experience of this patient cohort and describe the complications and imaging appearances that can be encountered during the follow-up period.

MATERIALS AND METHODS

Retrospective review of our Orthopaedic Oncology database was undertaken which has been collected over a 30-year period to identify patients that had undergone sacrectomy and ilio-lumbar reconstruction. Pre and post-operative imaging including radiographs, CT, and MRI was reviewed. These were viewed by two experienced musculoskeletal radiologists with consensus opinion if there was disagreement over the imaging findings. Data regarding patient demographics, tumor type, and dimensions was collected. Serial review of radiographs, CT, and MRI was performed to assess implant position and integrity, strut graft position and union, and for the presence of recurrence within the surgical bed.

RESULTS

Five male and two female patients (mean age 36 years, age range 15-54 years) were treated with this procedure. Histological diagnoses included chordoma, chondrosarcoma, osteosarcoma, and spindle cell sarcoma. Mean maximal tumor size on pre-operative imaging was 10.7 cm (range, 6-16 cm). Post-operative follow-up ranged from 10-46 months. A total of 76 imaging studies were reviewed. Commonly identified complications included vertical rod and cross-connector fracture and screw loosening. Fibula strut graft non-union and fracture was also evident on imaging review. Two patients demonstrated disease recurrence during the follow-up period.

CONCLUSIONS

This study demonstrates the spectrum and frequency of complications that can occur following sacrectomy and ilio-lumbar reconstruction for sacral neoplasia.

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.

Creation of false pedicles and a neo-pelvis for lumbopelvic reconstruction following en bloc resection of an iliosacral chondrosarcoma with lumbar spine extension: technical note

En bloc resection with negative tumor margins remains the principal treatment option for control or cure of primary pelvic chondrosarcomas, as current adjuvant therapies remain ineffective. Iliosacral chondrosarcomas with involvement of the sciatic notch are sufficiently challenging tumors. However, when there is concomitant lumbar extension requiring resection of the pedicles to maintain negative surgical margins, transpedicular screw fixation is not possible, making reconstruction of the lumbopelvic junction extremely challenging. A patient with an iliosacral chondrosarcoma with lumbar spine extension is presented in this report to illustrate a novel lumbopelvic spinal construct. Following combined external pelvectomy and hemisacrectomy with contralateral L3-5 hemilaminectomy and ipsilateral pediculotomy, bicortical transvertebral body screws were substituted for the missing pedicles, resulting in the creation of "false pedicles," which were further supplemented with an autologous vascularized fibular strut graft from the amputated lower limb and applied to the lateral aspect of the vertebral bodies. The creation of false pedicles allowed for a robust reconstruction of the lumbopelvic junction, including maintaining pelvic ring integrity with a "neo-pelvis", creating a functional load-bearing construct adequate for early mobilization and ambulation. The biomechanical dynamics of this unique construct are also discussed.

Surgical techniques for spinopelvic reconstruction following total sacrectomy: a systematic review

PURPOSE

To identify all available reconstruction methods for a total sacrectomy. Secondarily, we aimed to evaluate outcomes based on different interventions.

METHODS

We searched PubMed to identify sacral resections for tumors requiring internal fixation for stabilization. Demographic information, fixation techniques and postoperative outcomes were abstracted.

RESULTS

Twenty-three publications (43 patients) met inclusion criteria from an initial search of 856 (κ 0.93). Mean age was 37 years and follow-up was 33 months. Fixation methods included a combination of spinopelvic fixation (SPF), posterior pelvic ring fixation (PPRF), and/or anterior spinal column fixation (ASCF). For the purposes of analysis, patients were segregated based on whether they received ASCF. Postoperative complications including wound/instrument infections, GI or vascular complications were reported at a higher rate in the non-ASCF group (1.63 complications/patient vs. 0.7 complications/patient). Instrument failure was seen in 5 (16.1 %) out of the 31 patients with reported outcomes. Specifically, 1 out of 8 patients (12.5 %) with ASCF compared with 4 out of 23 patients (17.4 %) without ASCF had hardware failure. At final follow-up, 35 of 39 patients were ambulating.

CONCLUSION

While surgical treatment of primary sacral tumors remains a challenge, there have been advances in reconstruction techniques following total sacrectomy. SPF has shifted from intrapelvic rod and hook constructs to pedicle and iliac screw-rod systems for improved rigidity. PPRF and ASCF have adapted for deficiencies in the posterior ring and anterior column. A trend toward a lower rate of hardware failure emerged in the group utilizing anterior spinal column support. Despite a more involved reconstruction with ASCF, surgical complications such as infection rates and blood loss were lower compared to the group without ASCF. While we cannot definitively say one system is superior to the other, based on the data gleaned from this systematic review, it is our opinion that incorporation of ASCF in reconstructing the spinopelvic junction may lead to improved outcomes. However, most importantly, we recommend that the treating surgeon operate on patients requiring a total sacrectomy based on his or her level of comfort, as these cases can be extremely challenging even among experts.

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.

Posterior-Only Approach for En Bloc Sacrectomy

BACKGROUND:

En bloc resection of primary sacral tumors has a demonstrated survival benefit. Total and high sacral amputations are traditionally performed by using a staged anterior and subsequent posterior approach. However, we have found that en bloc resection and biomechanical reconstruction of the spinal column is possible from a posterior-only approach in many cases.

OBJECTIVE:

To assess our series of posterior-only sacrectomies, emphasizing postoperative complications and overall surgical and oncologic outcome.

METHODS:

Sixty-nine consecutive patients underwent sacral resections for tumor at our institution between 2004 and 2009. Medical records of all patients were reviewed, and patients were excluded if they had an intentional intralesional resection, hemipelvectomy, or a previous operation. The records of the resulting 36 consecutive patients who underwent primary posterior-only en bloc sacral resections were retrospectively reviewed.

RESULTS:

Of the posterior-only patients, all underwent midline posterior approaches for en bloc sacral resection. Sacral amputation was defined by the by sacral root preservation: total (2 cases), high (8 cases), middle (9 cases), low (12 cases), and distal (5 cases). Chordoma was the most common tumor type (30 cases), and surgical margins were marginal in 34 cases and contaminated in 2. Overall, there were 13 complications, including 9 wound infections/revisions. The extent of sacrectomy, and thus the extent of roots sacrificed, correlated with functional outcome.

CONCLUSION:

It may be possible to perform a posterior-only approach to en bloc sacral resections/reconstructions in patients with tumors that do not extend beyond the lumbosacral junction or invade the bowel requiring bowel resection and diversion.

Pelvic exenteration for advanced rectal cancer

SUMMARY Advanced rectal cancer is defined by local tumor invasion into adjacent structures and organs in the pelvis. A curative multimodal therapy approach for patients with advanced rectal cancer includes neoadjuvant treatment with subsequent pelvic exenteration. Pelvic exenteration is associated with high perioperative morbidity as this surgical procedure includes an extensive resection of pelvic anatomical planes with en bloc removal of the tumor and surrounding organs and structures. Safe reconstruction of the large pelvic floor defect is very important. Quality of life and oncological outcome after pelvic exenteration for advanced rectal cancer are good. In this article, we highlight important clinical and surgical aspects of pelvic exenteration for advanced rectal cancer and review the recent literature.

Expert's comment concerning Grand Rounds case entitled "a novel 'pelvic ring augmentation construct' for lumbo-pelvic reconstruction in tumor surgery" (by Sathya Thambiraj, Daren Forward, James Thomas and Bronek Boszczyk)

INTRODUCTION

Historically, metastatic spine tumor surgery has been palliative for pain control, to maintain neurologic and ambulatory function. The thought of curing cancer with limited metastatic disease by resecting the primary and the metastatic lesions is becoming more common. Multilevel spondylectomy for resection of metastatic disease has been reported in the literature, mostly at the thoracic or lumbar level with some success. Reconstruction of the lumbosacral junction after tumor resection is a difficult endeavor and several techniques have been utilized. Subcutaneous anterior pelvic fixation has been described for the treatment of unstable pelvic fractures.

MATERIALS AND METHODS

Review of the Grand Rounds case "A novel Pelvic Ring Augmentation Construct for Lumbo-Pelvic Reconstruction in Tumour Surgery" by Sathya Thambiraj, Daren Forward, James Thomas, Bronek Boszczyk and review of the pertinent literature.

CONCLUSION

The authors describe a novel percutaneous rod technique and construct for buttressing a posterior spinal construct to a subcutaneous anterior pelvic fixator after tumor resection of the lumbo-pelvic junction. They manage to salvage a difficult situation for which they should be commended. This technique may be useful in situations where instrumentation has to be preformed to the pelvis: i.e., in tumor reconstruction, fusions such as neuromuscular scoliotic disease to the pelvis, to augment a lumbo-pelvic construct when a nonunion occurs or in osteoporotic patients as a salvage procedure.

A novel "pelvic ring augmentation construct" for lumbo-pelvic reconstruction in tumour surgery

AIM

Reconstructing or augmenting the lumbo-pelvic junction after resection of L5 and part of the sacrum is challenging. Numerous lumbo-pelvic reconstruction methods based on posterior construct and anterior cages have been proposed for cases involving total sacrectomy and lumbar vertebrectomy. These constructs create long lever arms and generate high cantilever forces across the lumbo-sacral junction, resulting in implant failure or breakage. Biomechanical studies have shown that placing implants anterior to lumbo-sacral pivot point provides a more effective moment arm to resist flexion force and improves the ultimate strength of the construct. We present here a novel method to augment a lumbo-pelvic construction using a pelvic ring construct.

METHODS

A 69-year-old lady presented with implant failure of her two previous posterior lumbo-pelvic reconstructions performed by the authors. She initially presented, two and a half years previously with 6 months history of back pain with normal neurological function. MRI scans of her whole spine showed isolated secondaries in the lumbar spine (L4, L5) and sacrum (S1). An abdominal CT scan revealed a primary tumour in her right kidney. Briefly, the first surgery involved a single-stage removal of posterior elements of L4 and L5 and posterior stabilisation from L2 to pelvis, anterior resection of L4 and L5 and partially S1 with implantation of an expandable Synex II cage. The cage was replaced with an anterior rod construct from L2 and L3 to a trans-sacral screw a week later as it had dislodged. The second revision, 9 months later, involved removal of two posterior broken rods which were replaced and converted into a modified four-rod construct. While monitoring her progress, it was subsequently noted that the trans-sacral rod had broken. Therefore, it was decided to augment her lumbo-pelvic construct to prevent eventual catastrophic posterior construct failure. From a posterior approach, contoured rods were passed bilaterally along the inner table of the pelvis under the iliacus muscle up to the anterior border of the pelvis. Using T-connectors, the rods were connected to the posterior lumbo-pelvic construct. Thereafter, two anterior supra-acetabular pelvic screws were connected to a subcutaneously placed rod matched to the shape of the anterior abdominal wall. The pelvic ring construct was completed on connecting this rod with T-connectors to the free ends of the contoured iliac rods.

RESULTS AND CONCLUSION

There were no intra-operative complications. At the end of 12 months, she was mobilising with a frame, with no radiological evidence of failure of the construct. However, she died due to disease progression at the end of 15 months. Experience from one clinical case shows that such a construct is feasible and adds a technical option to the difficult reconstruction of lumbo-pelvic junction after tumour surgery.

5-Level spondylectomy for en bloc resection of thoracic chordoma: case report

BACKGROUND AND IMPORTANCE

Primary tumors of the spine are considered for en bloc resection to improve local control and even obtain cure. Anatomic restrictions often prohibit extensive resections with negative margins that are safe and feasible. We report the first case involving a patient with a large chordoma of the thoracic spine who underwent a successful 5-level spondylectomy with bilateral chest wall resection for en bloc resection without neurologic compromise.

CLINICAL PRESENTATION

A 26-year-old woman with a chest mass was found to have a T1-5 chordoma via a percutaneous biopsy. En bloc resection of the mass was thought to be the best option for long-term local control and possible cure. She presented without neurologic or pulmonary dysfunction. The patient underwent a 3-stage procedure. The first stage involved a posterior C2-T8 exposure, allowing release of posterior elements from C7 to T6 and instrumented stabilization from C2 to T8. T1-5 ribs were cut bilaterally, and 2 wire saws were placed ventral to the thecal sac at the C7-T1 and T5-6 disc levels. The second stage involved a right-sided thoracotomy, and the T5-6 wire saw was used to complete the lower osteotomy. The third stage involved completion of the C7-T1 osteotomy with the wire saw, delivery of the tumor specimen en bloc, ventral reconstruction of the spine with a titanium mesh cage, and bilateral thoracoplasty.

CONCLUSION

This is the first case report of a 5-level spondylectomy for en bloc resection of an extensive thoracic chordoma via a bilateral thoractomy without neurologic compromise.