Salvage reconstruction with vascularized fibular strut graft fusion using posterior approach in the treatment of severe spondylolisthesis

Free Fibular Flap and Fibular Graft Double-Strut Tunneling to Fill a Large Tibial Plateau Defect

Introduction

Bony defects resulting from trauma, osteomyelitis, and tumor resection pose significant reconstructive challenges. Free fibular flaps (FFFs) are an excellent option, especially for large defects in the tibia.

Case presentation

In this article, the authors review a case of a 60-year-old male who underwent FFF and fibular graft double-strut tunneling to fill a large tibial plateau defect.

Conclusion

The use of the FFF provides an excellent option for reconstructing long bone large defects (defects > 6 cm). The case presented in this report indicates an expanded application of this technique in treating defects secondary to chronic osteomyelitis in infected tibial plateau nonunion.

Pedicled Vascularized Bone Grafts for Posterior Lumbosacral Fusion: A Cadaveric Feasibility Study and Case Report

STUDY DESIGN

Cadaveric feasibility study and case report.

OBJECTIVE

To determine if it is feasible to rotate pedicled vascularized bone graft (VBG) from L1 to S1 via a posterior approach.

SUMMARY OF BACKGROUND DATA

VBG has been used to successfully augment fusion rates in various skeletal pathologies. Pedicled VBG has numerous advantages over free-transfer VBG, including the maintenance of a robust vascular supply to the graft without the need for vascular anastomoses. Pedicled VBG options have not been well described for posterior lumbosacral fusion.

METHODS

A multidisciplinary team of plastic surgeons and neurosurgeons hypothesized that it is feasible to rotate pedicled VBG from L1 to S1 via a posterior approach. In six cadavers, two VBG donor sites were evaluated: posterior element (PE-VBG) and iliac crest (IC-VBG). A single case report of a patient with lumbar Charcot joint treated with IC-VBG is also presented.

RESULTS

For the PE-VBG, the laminae and spinous processes were mobilized en bloc via Gill laminectomy on a unilateral sacrospinalis pedicle. Mean ± standard deviation (SD) length × width graft dimensions were 2.8±0.48 cm × 2.2±0.81 cm. The inter-transverse process (inter-TP) distance was less than the corresponding lamina length at all levels. For the IC-VBG, iliac crest was mobilized on a quadratus lumborum pedicle. Mean±SD length × width × thickness graft dimensions were 7.7±1.28 cm × 2.2±0.69 cm × 1.5±0.79 cm. The IC-VBGs reached from L1 (T12-S1) to S1 (S1-S3), and all IC-VBGs were able to cover three levels.

CONCLUSIONS

This feasibility cadaveric study and the case report are the first demonstrations that pedicled VBGs can be successfully applied to posterior lumbosacral spinal arthrodesis. Patients at high risk for nonunion may benefit from these strategies. Further clinical experience with these techniques is warranted.

LEVEL OF EVIDENCE

Level IV.

Vascularized Spinous Process Graft Rotated on a Paraspinous Muscle Pedicle for Lumbar Fusion: Technique Description and Early Clinical Experience

BACKGROUND

Vascularized bone grafts (VBGs) are described as having superior osteogenicity, osteoconductivity, and osteoinductivity compared with other graft types and have been used in high-risk patients to augment arthrodesis. Pedicled VBGs are rotated on an intact vascular pedicle and therefore maintain all the benefits of VBGs but avoid many of the challenges and additional morbidity of free-tissue transfer. This study describes a novel surgical technique for rotating vascularized spinous process into the posterolateral space for augmenting arthrodesis in patients undergoing posterolateral fusion (PLF).

METHODS

A technique is described for rotating the spinous process into the posterolateral space on an intact vascular pedicle of paraspinal muscle. Early clinical and radiographic outcomes are reported for 4 patients who have undergone this procedure.

RESULTS

Four patients were treated with a single or 2-level PLF combined with posterior, anterior, or lateral interbody fusion and vascularized spinous process graft. Three-month postoperative computed tomography scans demonstrated a dislodged graft in 1 patient and successful arthrodesis in 3 patients. Additional operative time taken for graft harvest and implantation ranged from 22 minutes for the first patient to 6 minutes for the fourth patient.

CONCLUSIONS

Rotation of vascularized spinous process graft for augmentation of posterolateral arthrodesis in the lumbar spine is a potentially safe, effective surgical technique that results in successful arthrodesis in as little as 3 months but requires further study. This technique is expected to add little additional time or morbidity to the traditional lumbar PLF because it requires no separate incision or additional bone removal.

Hollow modular anchorage (HMA) screws for anterior transvertebral fixation in high-grade spondylolisthesis cases requiring 360 degrees in-situ fusion

OBJECTIVE

360 degrees in-situ fusion for high-grade spondylolisthesis showed satisfying clinical long-term results. Combining anterior with posterior surgery increases fusion rates. Anteriorly inserted transvertebral HMA screws could be an alternative to strut graft constructs or cages, avoiding donor site complications. In addition, complete posterior muscle detachment is avoided and the injury risk of neural structures is minimized. This study investigates the use of HMA screws in this context.

MATERIAL AND METHODS

Five consecutive patients requiring L4-S1 in-situ fusion for isthmic spondylolisthesis (four Grade 3 and one Grade 4) were included. The L5/S1 level was fused with an HMA screw filled with local bone and bone morphogenic protein (BMP2), inserted via the L4/5 disc space level. An L4/5 stand-alone interbody fusion with additional minimal invasive posterior screw fixation was added.

RESULTS

Transvertebral insertion of the HMA device was accomplished via a retroperitoneal approach to L4/L5 in all cases without exposure of L5/S1. Blood loss ranged from 150 ml-350 ml. No intraoperative complication occurred. One patient developed posterior wound infection requiring debridement. Solid fusion was confirmed with a CT scan after 6 months in all patients. All patients improved to unrestricted activities of daily living with two being limited by occasional back pain.

CONCLUSIONS

HMA screws allow for effective lumbosacral fusion via a limited anterior exposure. This is technically easier than posterior exposure of the lumbosacral junction in high-grade spondylolisthesis requiring 360 degrees fusion.

Application of vascularized fibular graft for reconstruction and stabilization of multilevel cervical tuberculosis: A case report

Multilevel cervical reconstruction and fusion after cervical tuberculosis has always been a challenge. The current implantation materials for cervical fusion, including titanium mesh, cage, and plate are limited by its inferior biological mechanical characteristics and the properties of the metallic material. This has led to the increased risk of recurrent infection after surgery. In addition, the unique nature of tuberculosis infection results in the low rate of cervical fusion and high risk of recurrence. This case report presents 1 patient who suffered from long segmental cervical tuberculosis and had reconstruction surgery using a vascularized fibula graft. The patient had successful graft incorporation 3 months postsurgery and was followed-up for 30 months. In this review, we detail the advantages of using vascularized fibular grafts and compare it with other types of grafts.

Novel lumbosacral axial fixation techniques

For patients with low back pain secondary to pathological motion of an unstable lumbar motion segment, interbody fusion may be indicated. Numerous open and minimally invasive techniques have been traditionally used, but all suffer from shortcomings related to biomechanics or inherent iatrogenic destabilization. A novel transaxial approach to the lumbosacral junction has recently been described which appears to obviate many of the limitations of previous techniques. Preliminary results of the transaxial approach to lumbosacral fixation appear promising.

A modified technique for dowel fibular strut graft placement and circumferential fusion in the setting of L5-S1 spondylolisthesis and multilevel degenerative disc disease

BACKGROUND

Traditional techniques for the treatment of isthmic spondylolisthesis pass a fibular dowel graft across the L5-S1 disc by using the anterior portion of the L5 body.

OBJECTIVE

To introduce a technique for the treatment of isthmic spondylolisthesis in the setting of multilevel degenerative disc disease in adults. Our modified technique allows us to traverse the L5-S1 disc via the L4-5 disc space thereby treating the degenerated disc at L4-5 simultaneously.

METHODS

A standard anterior discectomy was performed on L4-5. Using biplanar fluoroscopy, a Kirschner wire was placed beginning at the anterior third of the L5 superior endplate and ending at S1. An anterior cruciate ligament reamer was used to make a channel for the fibular allograft. Then, a femoral ring allograft was placed in the disc space at L4-5, and standard anterior lumbar interbody fusions were performed at any additional cephalad level(s). Afterward, posterior instrumented fusion was performed to complement the anterior fusion procedure (except at L5), and wide decompression followed.

RESULTS

All patients presented with isthmic spondylolisthesis and all had multilevel fusions. The mean slip angle was 32.6 degrees (37.8 degrees preoperatively), and mean lumbar index was 67%. After the procedure, the average endplate-to-dowel angle was 107.1 degrees compared with 134 degrees. All patients had clinical and radiographic evidence of solid fusion without the need for revisions.

CONCLUSION

The proposed advantage of our modified technique is twofold. The graft is placed nearly perpendicular to the L5-S1 interface, as it will behave more efficiently with respect to interfragmental compression. Also, surgeons gain access to fuse L4-5 anteriorly and posteriorly.

The role of vascularized bone grafts in spine surgery

The use of vascularized bone grafts in complex spine reconstruction is particularly attractive in situations that involve large segmental bone defects, failed previous attempts at arthrodesis, poor soft tissue beds secondary to infection or radiation exposure necrosis or failed arthrodesis in neuromuscular disease processes. This article details the indications and rationale for vascularized bone grafting as well as the results of vascularized bone grafting of the spine.

Use of the Microvascular Free Fibula Transfer as a Salvage Reconstruction for Failed Anterior Spine Surgery due to Chronic Osteomyelitis

BACKGROUND

Several factors influence the osseous union of spinal fusions, including the substrate used for arthrodesis, the biology of the fusion bed, as well as local host factors. While cancellous bone grafting is useful in simple cases with no major bony defects, corticocancellous strut grafts are indicated in reconstructions requiring mechanical support. The size and location of the spinal defect to be reconstructed determine what type of vascularized bone graft is indicated. According to the literature, locations suitable for reconstruction using a microvascular free fibula graft include the cervical spine and, less frequently, the cervicothoracic, thoracic, thoracolumbar, and lumbar spine. Using the microvascular free vascularized fibula graft as a salvage procedure for failed anterior spine surgery due to bacterial spinal osteomyelitis has not been reported.

METHODS AND RESULTS

Four cases of spinal osteomyelitis after attempted spinal fusion are presented. In all cases, a microvascular free fibula graft was successfully used for secondary spinal fusion and clearance of documented bacterial osteomyelitis. The operative approach is described.

CONCLUSIONS

Use of the vascularized free fibula graft for correction of primary and secondary spinal deformities, as well as for reconstruction after excision of malignant spine tumors, has been well documented. On the basis of their experience, the authors also recommend microvascular fibula transplantation as a salvage procedure for failed anterior spine surgery due to chronic osteomyelitis.

Biomechanical evaluation of a novel lumbosacral axial fixation device

BACKGROUND

Interbody arthrodesis is employed in the lumbar spine to eliminate painful motion and achieve stability through bony fusion. Bone grafts, metal cages, composite spacers, and growth factors are available and can be placed through traditional open techniques or minimally invasively. Whether placed anteriorly, posteriorly, or laterally, insertion of these implants necessitates compromise of the anulus--an inherently destabilizing procedure. A new axial percutaneous approach to the lumbosacral spine has been described. Using this technique, vertical access to the lumbosacral spine is achieved percutaneously via the presacral space. An implant that can be placed across a motion segment without compromise to the anulus avoids surgical destabilization and may be advantageous for interbody arthrodesis. The purpose of this study was to evaluate the in vitro biomechanical performance of the axial fixation rod, an anulus sparing, centrally placed interbody fusion implant for motion segment stabilization.

METHOD OF APPROACH

Twenty-four bovine lumbar motion segments were mechanically tested using an unconstrainedflexibility protocol in sagittal and lateral bending, and torsion. Motion segments were also tested in axial compression. Each specimen was tested in an intact state, then drilled (simulating a transaxial approach to the lumbosacral spine), then with one of two axial fixation rods placed in the spine for stabilization. The range of motion, bending stiffness, and axial compressive stiffness were determined for each test condition. Results were compared to those previously reported for femoral ring allografts, bone dowels, BAK and BAK Proximity cages, Ray TFC, Brantigan ALIF and TLIF implants, the InFix Device, Danek TIBFD, single and double Harms cages, and Kaneda, Isola, and University plating systems.

RESULTS

While axial drilling of specimens had little effect on stiffness and range of motion, specimens implanted with the axial fixation rod exhibited significant increases in stiffness and decreases in range of motion relative to intact state. When compared to existing anterior, posterior, and interbody instrumentation, lateral and sagittal bending stiffness of the axial fixation rod exceeded that of all other interbody devices, while stiffness in extension and axial compression were comparable to plate and rod constructs. Torsional stiffness was comparable to other interbody constructs and slightly lower than plate and rod constructs.

CONCLUSIONS

For stabilization of the L5-S1 motion segment, axial placement of implants offers potential benefits relative to traditional exposures. The preliminary biomechanical data from this study indicate that the axial fixation rod compares favorably to other devices and may be suitable to reduce pathologic motion at L5-S1, thus promoting bony fusion.

Evaluation and management of high-grade spondylolisthesis in adults

STUDY DESIGN

A retrospective review was performed on 21 adult patients surgically treated with high-grade spondylolisthesis (Grade III, IV, or V). Additionally, the natural history, classification, and surgical alternatives for high-grade spondylolisthesis in the adult are discussed through literature review.

OBJECTIVES

The purpose of this article is to review the clinical and radiographic outcomes of surgical treatment of high-grade spondylolisthesis in the adult from a single institution. The natural history and treatment options for these adults are described in this review.

SUMMARY OF BACKGROUND DATA

High-grade spondylolisthesis is typically diagnosed and treated in the child or adolescent. Most patients with high-grade spondylolisthesis received surgical treatment during their adolescence. Some patients, however, remain minimally symptomatic for life without surgery. Little has been written on the natural history or treatment of adults with high grades of spondylolisthesis. Most of the published reports on the surgical treatment of high-grade spondylolisthesis pertain to skeletally immature patients and maybe include a few adults in their series. Nonetheless, the different techniques of surgical treatment for high-grade spondylolisthesis that have been described in these studies can help the spinal surgeon in treatment options for this rare but difficult spinal deformity.

METHODS

A literature review of the published manuscripts on the treatment of high-grade spondylolisthesis was performed with particular attention to the natural history and surgical treatment involving adult patients. Adult patients (older than 21 years) with high-grade spondylolisthesis treated surgically were retrospectively reviewed. Patients' clinical charts and radiographs were reviewed before and after surgery. Determination of fusion success, clinical outcome, and complications were performed.

RESULTS

Twenty-one consecutive adults with high-grade spondylolisthesis who underwent lumbar spinal surgery were review retrospectively between 1990 and 2004. There were 13 females and 8 males with an average age of 35 years (range, 21-68 years). The average follow-up was 6.6 years. There were 11 Grade III, 6 Grade IV, and 4 Grade V slips, including 4 acquired and 17 developmental spondylolistheses. There were no pseudarthroses or significant instrumentation failures. There was 1 case of a complete cauda equina syndrome on a patient with preoperative symptoms of an incomplete cauda equina syndrome.

CONCLUSIONS

Adult patients with high-grade spondylolisthesis not responding to nonoperative treatment can be stabilized in situ with posterior instrumentation from L4 to S1. The use of adjunctive fixation with iliac screws and/or transvertebral screws is recommended for the adult patient, particularly in revision or unstable cases. Reduction of the slipped vertebrae remains controversial for all grades of spondylolisthesis and more so for the adult patient. Partial reduction of the slip angle, decreasing the lumbosacral kyphosis, should be considered if significant sagittal malalignment is present or to improve arthrodesis success. Anterior column support should be performed, particularly when reduction has been obtained. Anterior column support can be performed, anteriorly or posteriorly, either by using inter vertebral body structural strut support or with a transsacral fibular dowel to improve stability and success of arthrodesis.

New Percutaneous Access Method for Minimally Invasive Anterior Lumbosacral Surgery

Preliminary cadaver, animal, and human studies were performed to determine the feasibility of axial anterior lumbosacral spine access using a percutaneous, presacral approach. Custom instruments were directed under fluoroscopic guidance along the midline of the anterior sacrum to the surface of the sacral promontory where an axial bore was created into the lower lumbar vertebral bodies and discs. Imaging and gross dissection were performed in cadavers and animals. The procedure was used for lumbosacral biopsy in human subjects guided by intraoperative imaging and clinical monitoring. All procedures were technically successful. This study demonstrates the feasibility of the axial access technique to the anterior lower lumbar spine.