Corpectomy Cage Research Articles

A rib-sparing unilateral transpedicular thoracic corpectomy using the ultrasonic bone scalpel: a novel technique and pictorial guide

BackgroundThe thoracic corpectomy is a well-described technique for the surgical treatment of vertebral column fractures with spinal canal compromise. Traditionally, the posterolateral approach to this procedure required the removal of the approach side rib in order to introduce the corpectomy cage. This rib removal, however, has been identified as a major contributor to post-operative morbidity. Rib-sparing techniques have been shown to be beneficial in minimizing post-operative morbidity in non-spinal surgeries. Herein, we present a previously undescribed technique of a rib-sparing thoracic corpectomy that avoids sequalae of rib resection with assistance from an ultrasonic bone scalpel (UBS).MethodsA retrospective chart review was conducted on patients having undergone this thoracic corpectomy technique. Data on patient age at operation, indication for surgery, number of corpectomies per case, estimated blood loss (EBL), operative time (OT), intra-operative complications, and post-operative length of stay (LOS) were collected and analyzed. A pictorial step-by-step guide was created to highlight the advantages of an entirely posterior rib-sparing unilateral transpedicular technique for thoracic corpectomy.ResultsA total of 36 corpectomies were performed on 32 patients between August 2015 and March 2023. Patients ages ranged from 17 to 85 years (mean = 63). The most common indication was oncological (n = 22, 69%), followed by degenerative/traumatic deformity (n = 7, 22%), and infection (n = 3, 9%). For the cases for which data was accessible, mean EBL was 853 cc and mean OT was 178 min. The average post-operative LOS was 6.5 days.ConclusionThe described surgical approach makes it possible to create a transpedicular corridor with no costectomy for implantation of an expandable titanium cage and anterior column reconstruction. The use of the UBS in this approach is critical as it minimizes bony removal and avoids sequelae of rib resection. The described technique has the potential to circumvent post-costectomy pain, thereby expediting post-operative recovery after thoracic corpectomy.

290 A Rib-Sparing Unilateral Transpedicular Thoracic Corpectomy Using the Ultrasonic Bone Scalpel: A Novel Technique and Pictorial Guide

INTRODUCTION: Posterior thoracic corpectomies typically require removal of the costotransverse articulation and some amount of the adjoining rib, an accompaniment that has been shown to result in significant post-operative morbidity. There are several well-described approaches to pathology of the thoracic spine, each with advantages, disadvantages, and inherent limitations. METHODS: The technique is demonstrated step-by-step in a videographic pictorial description of the procedure performed on both a molded plastic spine model and on a cadaveric specimen. A retrospective chart review was conducted on patients having undergone this thoracic corpectomy technique since its implementation at the senior author’s institution. Patient data, operative metrics, and outcomes were collected and analyzed. RESULTS: A total of 36 corpectomies were performed on 32 patients (mean age = 63 years). There were oncological (n = 22, 69%), degenerative/traumatic (n = 7, 22%), and infection (n = 3, 9%) indications. EBL averaged 853 cc for 30/32 cases. Operative time averaged 177.83 minutes. Length of stay averaged 6.47 days. One clinically inconsequential iatrogenic durotomy occurred. One patient had a surgical site infection three weeks later that required wound washout without hardware revision. CONCLUSIONS: Rib resection correlates with significant post-operative pain. This thoracic corpectomy technique mitigates morbidity by avoiding manipulation, destabilization, or resection of the rib, potentially permitting faster recovery and discharge. The technique is dependent on the UBS as it expediently creates a tailored window for an expandable corpectomy cage. A rib-sparing thoracic corpectomy can be effectively, efficiently, and safely performed using a combination of the UBS and an expandable cage during a single stage posterior-only unilateral transpedicular approach with which most spine surgeons are familiar.

Ten-Year Risk of Recall of Novel Spine Devices.

Observational epidemiological study. This study's primary objective was to examine the risk of recall for novel spine devices over time. Secondarily, we sought to analyze interbody fusion and vertebral body replacement (VBR) devices (corpectomy cages) as a risk factor for recall. The recall risk of a novel spine device over time has not been reported. In addition, FDA regulations were lowered for interbody fusion devices to enter the market in 2007. As well, VBR implants were recently approved by the FDA for use in the cervical spine in 2015. Spine devices cleared between January 1, 2008 and December 31, 2018 were identified from the FDA's 510(k) database. All recall data were collected from the database in January 2021 to provide a 2-year minimum follow-up for a recall to occur. Product labels were used to classify interbody fusion and VBR devices. Cumulative incidence function was conducted to compare the overall risk of recall for FDA-cleared spine devices, and the hazard ratio determined for VBR and all other devices versus interbody implants during the study period. A total of 2384 spine devices were cleared through 510(k) in the study period. The hazard of recall at 5 years was 5.3% (95% CI: 4.4%-6.2%) and 6.5% (95% CI: 5.4%-7.7%) at 10 years. No significant difference in recall risk was identified for interbody fusion and VBR devices. The risk of recall at 5 and 10 years of a novel spine device is about half the 12% rate reported for orthopedic devices in general. Despite lowered FDA regulations for interbody fusion devices and recent approval for VBR device use in the cervical spine, no increased risk of recall was detected. Further research is necessary to explain the reason for the lower risk of recall with spine devices. 4.

Novel Nerve-Sparing In Situ Assembly of an Expandable Titanium Cage to Maximize Endplate Coverage After Posterior Corpectomy for Comminuted Lumbar Burst Fractures.

The ability to maximize corpectomy cage endcap size and vertebral endplate coverage after corpectomy for lumbar burst fractures (L1-L5) is limited by the presence of lumbar nerve roots and the larger cross-sectional area of the lumbar endplates relative to the restrictive corridor for cage insertion. This work aims to provide details and clinical examples of a novel operative technique for 3-column reconstruction and stabilization of comminuted lumbar burst fractures. Through a standard posterior midline approach and following posterior instrumentation and lateral extracavitary corpectomy, an in-situ assembly of a modular corpectomy cage that respects adjacent neural structures, restores segmental alignment, and maximizes endplate coverage across a lordotic segment is completed. Radiographic evidence of anatomic spinal reconstruction and stabilization with complete or near-complete endplate coverage without incurrence of new clinical deficit after this novel treatment of lumbar burst fractures. The fixation approach described in this report may be a valuable modification to a long-standing technique used for treating comminuted lumbar burst fractures (L1-L5) from a posterior-only approach without incurring additional neurological deficits and by improving endplate and apophyseal ring coverage.

Posterior-only approach in patients with poor general condition and spinal metastatic vertebral fracture

PurposeThe surgical treatment of spinal metastases is mostly palliative in nature and focuses on improving the quality of life of patients. The posterior transpedicular surgical approach provides circumferential 360° decompression, allows reconstruction and stabilisation to be achieved in a single session and can be performed using an open, mini-open or minimally invasive approach. We present and discuss the surgical techniques and outcomes for patients with single-level metastatic spinal disease and in poor general condition who underwent surgery via the posterior-only transpedicular corpectomy approach and reconstruction with expandable corpectomy cages. MethodsPatients with a single level thoracolumbar metastatic disease (T3-L5) and a Karnofsky score of ≤70, who underwent a complete posterior transpedicular corpectomy with expandable cage reconstruction of the anterior spinal column were retrospectively reviewed. Patients’ demographics, SINS, modified Tokuhashi scores as well as preoperative and postoperative ASIA scale, Karnofsky scores, VAS scores and vertebral height/Cobb angle values were analysed. ResultsA total of 44 patients (24 M/20 F) (mean age 53.25±21.26 years) met the inclusion criteria. The modified Tokuhashi scores were as follows: score 0–8, 5 (11.4%) patients; score 9–11, 14 (31.8%) patients; and score 12–15, 25 (56.8%) patients. There were significant improvements in the postoperative VAS scores (mean 7.7–2.9), Karnofsky scores (mean 63.3–79.6) as well as the Cobb angles (18.6–12.8°) and vertebral height. Thirtyfive patients showed improved neurological function by at least one ASIA grade, whereas 9 showed no improvement during the postoperative period. ConclusionsThis technique, which has a low complication rate and a short recovery time, can help achieve satisfactory results even in patients with poor metabolic profiles and Karnofsky scores in the preoperative period. Further clinical studies with large patient groups are warranted to confirm the results of this study.

Posterior-only approach in patients with poor general condition and spinal metastatic vertebral fracture

PurposeThe surgical treatment of spinal metastases is mostly palliative in nature and focuses on improving the quality of life of patients. The posterior transpedicular surgical approach provides circumferential 360° decompression, allows reconstruction and stabilisation to be achieved in a single session and can be performed using an open, mini-open or minimally invasive approach. We present and discuss the surgical techniques and outcomes for patients with single-level metastatic spinal disease and in poor general condition who underwent surgery via the posterior-only transpedicular corpectomy approach and reconstruction with expandable corpectomy cages. MethodsPatients with a single level thoracolumbar metastatic disease (T3-L5) and a Karnofsky score of ≤70, who underwent a complete posterior transpedicular corpectomy with expandable cage reconstruction of the anterior spinal column were retrospectively reviewed. Patients’ demographics, SINS, modified Tokuhashi scores as well as preoperative and postoperative ASIA scale, Karnofsky scores, VAS scores and vertebral height/Cobb angle values were analysed. ResultsA total of 44 patients (24 M/20 F) (mean age 53.25±21.26 years) met the inclusion criteria. The modified Tokuhashi scores were as follows: score 0–8, 5 (11.4%) patients; score 9–11, 14 (31.8%) patients; and score 12–15, 25 (56.8%) patients. There were significant improvements in the postoperative VAS scores (mean 7.7–2.9), Karnofsky scores (mean 63.3–79.6) as well as the Cobb angles (18.6–12.8°) and vertebral height. Thirtyfive patients showed improved neurological function by at least one ASIA grade, whereas 9 showed no improvement during the postoperative period. ConclusionsThis technique, which has a low complication rate and a short recovery time, can help achieve satisfactory results even in patients with poor metabolic profiles and Karnofsky scores in the preoperative period. Further clinical studies with large patient groups are warranted to confirm the results of this study.

Minimally invasive lateral retroperitoneal transpsoas approach for lumbar corpectomy and fusion with posterior instrumentation.

In this video, the authors highlight the operative treatment of a 55-year-old man with chronic osteomyelitis discitis. The operation entailed a minimally invasive lateral retroperitoneal transpsoas approach for L3 and L4 corpectomies, L2–5 interbody fusion, and L2–5 minimally invasive posterior instrumentation. The operation proceeded in two stages, beginning in the lateral position with corpectomy of the L3 and L4 vertebral bodies and placement of a corpectomy cage. After closure of this access wound, the patient was turned to a prone position for the posterior element of the operation. Posterior instrumentation was placed with pedicle screws at L2 and L5.The video can be found here: https://stream.cadmore.media/r10.3171/2022.3.FOCVID2210

Cervical vertebral body replacement using a modern in situ expandable and angulable corpectomy cage system: early clinical and radiological outcome

Purpose Vertebral body replacement (VBR) cages are commonly implanted to reconstruct the cervical vertebrae in cases of tumour, trauma, spondylodiscitis, and degeneration. Expandable cages have been widely used for this purpose; however, the lacking congruence at the implant-bone interface and consequent implant displacement were considered as a serious drawback of such systems. Aim of this study is to evaluate the early clinical and radiological outcome of a modern in situ not only expandable but also angulable cervical corpectomy cage system. Methods A total of 42 patients who underwent a single or multilevel cervical VBR procedure were included and retrospectively evaluated in this single-centre case series. The neurological status was assessed using American Spinal Injury Association (ASIA) score. Complications were categorized into surgical (including implant-associated) and general medical. Radiographic parameters included regional angulation, segmental height, and coronal alignment. Results Mean age was 59.5 ± 20.6 years. The recorded ASIA score improved postoperatively by 10 points (p 0.0001). Surgical including implant-associated complication rates were 19.05%. Radiographic evaluation showed a height gain of 11.2 mm (p < 0.0001), lordotic correction of 7° (p < 0.0001), and coronal alignment of 3° (p < 0.0001). At the last follow-up, loss of angulation correction of 1.9° (p 0.0002), subsidence of 1.92 mm (p 0.0006), and fusion rates of 68.42% were observed. Conclusions The use of an in situ angulable and expandable cage system in cervical VBR seems to offer better results compared to conventional static or expandable cages regarding segmental height gain, lordotic correction, and clinical improvement as well as low complication and revision rates. Significant height gain in multilevel surgeries is associated with higher rates of implant-associated complications.

Catastrophic delayed cervical arthroplasty failure: illustrative case.

BACKGROUNDCervical disc replacement (CDR) is an increasingly used alternative to fusion for symptomatic cervical disc disease. While more studies have suggested favorability of CDR over fusion procedures, limited data exist regarding implant fatigability. Here, the authors present a unique and previously unreported failure of the M6-C prosthesis causing spinal cord injury.OBSERVATIONSA 49-year-old female with history of cervical degenerative disease and prior C4–7 M6-C arthroplasty presented 9 years later after a minor fall from standing. She endorsed bilateral hand numbness ascending to forearms and shoulders, with dysesthesias and weakness. Imaging showed fractured arthroplasty penetrating the spinal cord. Revision surgery found a ruptured arthroplasty annulus with metal piece piercing the spinal cord. Partial C4 and C5 corpectomy was performed to remove the integrated fins of the arthroplasty and inspect the cord and dura. This was reconstructed with a corpectomy cage and plate. The patient made an excellent recovery, with improvement in her weakness and resolution of her sensory symptoms.LESSONSPossibility of fatigue-related failures presenting years after implantation have only been infrequently reported but can be catastrophic for patients. The authors encourage further discussions in this area, increased counseling with patients, and recommend a patient registry to better document adverse events.

An Alternative Technic for Cervical Fusion, Circularly Placed Bone Graft: Technical Note

Despite the highly developed spinal implants and surgical techniques in spinal stabilization, fusion failure is still the most important problem today. Among the factors that play a role in the success of spinal fusion, are type of graft material, contact of the fusion area with the graft tissue on the widest possible surface, good blood supply of the ends of the bone tissue that will fuse with the surrounding muscle and soft tissue, prevention of the movement of bone tissues that will be fused and placement of appropriate graft tissue in the targeted area for fusion. Therefore, we have developed and evaluated the radiological and clinical follow-up of an alternative cage - graft placement technique aimed at creating a large bone-graft area, which is one of the main conditions for the formation of fusion, and using it. In this new alternative technique we applied, we observed that the graft material that contacted the anterior and lateral faces of the cervical corpectomy cage with plates and completely filled them in a circular style formed a radiologically circular-style bone fusion after placement in this way. We believe that this graft placement will reduce possible instability.

First technical report of a pediatric case with thoracic Langerhans cell histiocytosis: Gross total tumor removal, corpectomy, and 360° stabilization via posterolateral approach at a single stage.

Background:Langerhans cell histiocytosis (LCH) is a rare nonmalignant disease characterized by a clonal proliferation of mononuclear cells called Langerhans histiocytes and infiltrates surrounding tissues, mostly self-limiting and usually occurring in the first two decades of life. Vertebral involvement is rare, mostly seen in the thoracic region, and involves the anterior elements of the corpus. In the literature, several treatment options and surgical approaches have been reported concerning the treatment of this disease and surgery.Case Presentation:We report an 18-month-old male with thoracic LCH who underwent surgery due to progressive neurological deficit. Gross total removal of the tumor with one level corpectomy in this patient was achieved via a posterolateral approach with postoperative functional improvement. The surgical cavity was supported by corpectomy cage and unilateral screw-rod fixation system at the same stage.Conclusion:Gross total tumor removal, corpectomy, and 360° stabilization via posterolateral approach at a single stage are safe, effective, and definite neurosurgical methods in terms of providing neurological recovery, long-term tumor-free survival, and spinal stability.

Partial Costotransversectomy and Corpectomy for Thoracic Spinal Metastatic Disease: Operative Technique and Nuances: 2-Dimensional Operative Video.

We describe the operative approach and management for thoracic metastatic disease in a 78-yr-old man with worsening mechanical lower back and left-sided thoracic radicular pain. Imaging of the thoracic spine revealed an osteolytic T11 mass with destruction of the left T11 pedicle and transverse process. Biopsy confirmed spinal metastasis from the liver. Preoperative angiogram was completed for localization of the artery of Adamkewicz and microparticle embolization of the left T11 intercostal artery. Surgical resection was supplemented with electrophysiological monitoring and neuronavigation. The corpectomy was approached by resecting the medial aspect of the rib, transverse process, and pedicle, which were all invaded with tumor. The left T11 nerve root was isolated and sacrificed to allow for placement of the expandable corpectomy cage and also resulted in sustained relief of the patient's radicular pain. The patient recovered from surgery well, with postoperative improvement of his pain. This case highlights the complex technical nuances of this procedure, and the importance of a thorough preoperative evaluation, including angiography, as proper identification of the artery of Adamkewitz can prevent severe neurological deficit from a spinal cord stroke. The patient consented to the procedure.

Improvement in vertebral endplate engagement following anterior column reconstruction using a novel expandable cage with self-adjusting, multiaxial end cap

BackgroundDestabilization of the vertebral column – as seen in trauma and metastatic spine disease – often requires corpectomy and anterior column reconstruction. Stresses applied to the implant can lead to subsidence, ultimately requiring in surgical revision. Here we report a cadaveric investigation of a novel expandable corpectomy cage with a self-adjusting, multiaxial end cap. MethodsFour cadaveric T11-sacrum spines (mean 67.3 yr; 75% female) were treated with L2 corpectomy and T12-L4 pedicle screw fusion. Pressure sensors were applied to the L1 and L3 endplates and anterior column reconstruction was performed with either a standard expandable corpectomy cage (T2A), an expandable corpectomy cage with a self-adjusting, multiaxial end cap (T2S), or the latter cage with oblong, extended end caps (T2S + EE). Total contact area was compared pre- and post-reduction using ANOVA general linear model. ResultsPre-reduction, the T2S constructs had a trend of higher surface contact than the conventional T2A constructs, though the results were not significant (p = 0.068); however, T2S + EE constructs did produce significantly larger contact with vertebral endplates (p = 0.04). The difference was also significant for both conditions following compression (p < 0.01 for both constructs). ConclusionsThe use of an expandable corpectomy cage with a self-adjusting, multiaxial end cap produces significant increases in vertebral endplate contact area. These in vitro data suggest that the self-adjusting, multiaxial end cap may serve to decrease the risk of subsidence in patients undergoing anterior column resection and reconstruction. Clinical data would be required to confirm the relationship between endplate contact area and risk of subsidence.

Four-Level Vertebrectomy for En Bloc Resection of a Cervical Chordoma

Chordomas are locally aggressive tumors that can involve multiple levels of the spine and are difficult to resect. We present our technique for 4-level en bloc cervical spondylectomy for a locally aggressive chordoma. A 37-year-old woman presented with a 6-month history of dysphagia and a large indurated cervical mass. Imaging showed an enhancing lesion involving C3-6. Needle biopsy confirmed the diagnosis of chordoma. En bloc resection was chosen to maximize her chances of disease-free survival. A 360° approach was deemed necessary. We posteriorly disconnected the vertebral bodies and skeletonized the bilateral vertebral arteries and nerve roots. The interspinous and yellow ligaments and the spinous processes were spared to maintain a solid posterior tension band, as previously described approaches that had sacrificed these elements had a high rate of instrumentation failure. After posterior instrumentation, a wide anterior approach enabled us to resect the tumor attached to the vertebral bodies of C3-6 as 1 specimen. A 4-level corpectomy cage and plate were used for anterior instrumentation. The patient tolerated the surgery well. She needed a temporary gastrostomy, and she had a right C5 palsy that progressively recovered. Follow-up imaging showed no tumor recurrence and good bony fusion. En bloc resection as part of a multidisciplinary team approach remains the mainstay of spinal chordoma treatment. Modern instrumentation and careful dissection can provide good results even in locally advanced cases.

Clinical Comparison of Surgical Constructs for Anterior Cervical Corpectomy and Fusion in Patients With Cervical Spondylotic Myelopathy or Ossified Posterior Longitudinal Ligament: A Systematic Review and Meta-Analysis.

This is a systematic review and meta-analysis. To examine the differences in outcomes among current constructs and techniques for anterior cervical corpectomy and fusion (ACCF) in patients with single or multiple level cervical myelopathy (CM) secondary to cervical spondylosis or ossified posterior longitudinal ligament. The natural history of CM can be a progressive disease process. In such cases, where surgical decompression is indicated to halt the progression, ACCF is typically chosen for pathology located posterior to the vertebral body. Numerous studies have shown that decompression with appropriate stabilization not only halts progression, but also improves patient outcomes. However, several constructs are available for this procedure, all with variable outcomes. A systematic review was conducted using Cochrane Database, Medline, and PubMed. Only studies with a minimum patient population of 10, reporting on CM because of cervical spondylosis or ossified posterior longitudinal ligament were included; a minimum follow-up period of 12 months and 1 clinical and/or radiographic outcome were required. Studies examining patients with cervical trauma/fracture, tumor, and infection or revision cases were excluded. Data analysis was carried out with Microsoft Excel. A total of 30 studies met the inclusion criteria for qualitative analysis, while 26 studies were included for quantitative analysis. Constructs that were reported in these studies included titanium mesh cages, nano-hydroxyapatite/polyamide 66 composite struts, bone graft alone, expandable corpectomy cages, and polyetheretherketone cages. Clinical outcomes included Japanese Orthopaedic Association and modified Japanese Orthopaedic Association scores, Visual Analog Scale scores, Neck Disability Index scores, and Nurick grades. Radiographic outcomes included C2-C7 and segmental Cobb angles and pseudarthrosis rates. Each construct type had variable and unique benefits and shortcomings. ACCF is a common surgical option for CM, despite carrying certain risks expected of any anterior cervical approach. Several constructs are available for ACCF, all with variable clinical and radiographic outcomes.

Cervical corpectomy for sub-axial retro-vertebral body lesions

BackgroundThe sub-axial vertebrae are formed of body, pedicles, laminae, facets, and spinous process. Cervical cord compression by anteriorly located retro-vertebral traumatic, inflammatory, neoplastic, and degenerative lesions is not rare, and in such cases, simple discectomy does not solve the problem. Corpectomy, grafting, and plating may help in management of these dangerous lesions.MethodsFrom May 2014 to December 2016, 30 cases with cervical myelopathy due to anteriorly located retro-vertebral traumatic, inflammatory, neoplastic, and degenerative lesions were operated upon by single, double, or triple levels corpectomy, grafting by bone graft or corpectomy cage and plating. Patients were followed up for 1 to 3 years both clinically and radiologically.ResultsImprovement of myelopathic manifestations (partial or complete) occurred in all cases within a variable time from 3 to 15 months. Bony fusion was sound in 27 cases and poor in 3 cases. Post-operative complications were mild and reversible.ConclusionsCorpectomy, grafting, and plating give a very good decompressive chance to the compressed cord by retro-vertebral lesions without any added risk.

Preventing Construct Subsidence Following Cervical Corpectomy: The Bump-stop Technique.

Cervical corpectomy is a viable technique for the treatment of multilevel cervical spine pathology. Despite multiple advances in both surgical technique and implant technology, the rate of construct subsidence can range from 6% for single-level procedures to 71% for multilevel procedures. In this technical note, we describe a novel technique, the bump-stop technique, for cervical corpectomy. The technique positions the superior and inferior screw holes such that the vertebral bodies bisect them. This allows for fixation in the dense cortical bone of the endplate while providing a buttress to corpectomy cage subsidence. We then discuss a retrospective case review of 24 consecutive patients, who were treated using this approach, demonstrating a lower than previously reported cage subsidence rate.

Suspension of the spinal dura mater to the corpectomy cage with tack-up sutures for bleeding control and prevention of epidural hematoma: operative technique

Suspension of the spinal dura mater to the corpectomy cage with tack-up sutures for bleeding control and prevention of epidural hematoma: operative technique

Anterior cement augmentation of adjacent levels after vertebral body replacement leads to superior stability of the corpectomy cage under cyclic loading—a biomechanical investigation

BackgroundIn the operative treatment of osteoporotic vertebral body fractures, a dorsal stabilization in combination with a corpectomy of the fractured vertebral body might be necessary with respect to the fracture morphology, whereby the osteoporotic bone quality may possibly increase the risk of implant failure. To achieve better stability, it is recommended to use cement-augmented screws for dorsal instrumentation. Besides careful end plate preparation, cement augmentation of the adjacent end plates has also been reported to lead to less reduction loss. PurposeThe aim of the study was to evaluate biomechanically under cyclic loading whether an additional cement augmentation of the adjacent end plates leads to improved stability of the inserted cage. Study Design/SettingMethodical cadaver study. Materials and MethodsFourteen fresh frozen human thoracic spines with proven osteoporosis were used (T2–T7). After removal of the soft tissues, the spine was embedded in Technovit (Kulzer, Germany). Subsequently, a corpectomy of T5 was performed, leaving the dorsal ligamentary structures intact. After randomization with respect to bone quality, two groups were generated: Dorsal instrumentation (cemented pedicle screws, Medtronic, Minneapolis, MN, USA)+cage implantation (CAPRI Corpectomy Cage, K2M, Leesburg, VA, USA) without additional cementation of the adjacent endplates (Group A) and dorsal instrumentation+cage implantation with additional cement augmentation of the adjacent end plates (Group B). The subsequent axial and cyclic loading was performed at a frequency of 1 Hz, starting at 400 N and increasing the load within 200 N after every 500 cycles up to a maximum of 2,200 N. Load failure was determined when the cages sintered macroscopically into the end plates (implant failure) or when the maximum load was reached. ResultsOne specimen in Group B could not be clamped appropriately into the test bench for axial loading because of a pronounced scoliotic misalignment and had to be excluded. The mean strength for implant failure was 1,000 N±258.2 N in Group A (no cement augmentation of the adjacent end plates, n=7); on average, 1,622.1±637.6 cycles were achieved. In Group B (cement augmentation of the adjacent end plates, n=6), the mean force at the end of loading was 1,766.7 N±320.4 N; an average of 3,572±920.6 cycles was achieved. Three specimens reached a load of 2,000 N. The differences between the two groups were significant (p=.006 and p=.0047) regarding load failure and number of cycles. ConclusionsAdditional cement augmentation of the adjacent end plates during implantation of a vertebral body replacement in osteoporotic bone resulted in a significant increased stability of the cage in the axial cyclic loading test.

Comparison of posterior 1/3 corpectomy reconstruction versus subtotal corpectomy reconstruction for thoracolumbar burst fractures

Objective To compare posterior 1/3 corpectomy versus subtotal corpectomy in recon-struction of thoracolumbar burst fractures. Methods A prospective study was conducted in the patients who were admitted into our department for treatment of thoracolumbar burst fracture between January 2010 and December 2012. Eligible patients were randomized into an experimental group (28 cases) and a control group (34 cases). The experimental group accepted posterior 1/3 corpectomy followed by reconstruction of the in-jured vertebrae using our self-designed gate-like cage while the control group subtotal corpectomy followed by cylinder mesh cage reconstruction. Surgery time, intraoperative blood loss, neurological function improvement according to American Spinal Injury Association (ASIA) grading, visual analogue scale (VAS) score, verte-bral height, kyphosis angle and fusion time were recorded before surgery, after surgery and at the final fol-low-up in both groups. Vertebral height loss was measured to evaluate endplate subsidence at the final fol-low-up. Results All the patients were available for 24-month follow-up. All the incisions healed by one intention, and no incision infection, aggravation of neural impairment symptoms or implant breakage oc-curred. The experimental group achieved significantly less surgery time and blood loss, significantly better fusion rates at 3, 6, and 9 months after surgery, and significantly lower VAS score at the final follow-up than the control group(P 0.05), but the VAS score and vertebral height loss were significantly lower in the experimental group than in the control group(P 0.05). Conclusions Posterior 1/3 corpectomy followed by gate-like cage reconstruction is an innovative technique for thoracolumbar fractures which can promote early fusion and reduce endplate subsidence. It is as fine as traditional subtotal corpectomy plus cylinder cage reconstruction in neurological function improvement and kyphosis correction. Key words: Thoracic vertebrae; Lumber vertebrae; Fracture fixation, internal; Posterior 1/3 corpectomy and reconstruction