Initial experience with the use of an expandable titanium cage as a vertebral body replacement in patients with tumors of the spinal column: a report of 95 patients

Torque forces of expandable titanium vertebral body replacement cages during expansion and subsidence in the osteoporotic lumbar spine

BACKGROUND

The application of expandable titanium-cages has gained widespread use in vertebral body replacement for indications such as burst fractures, tumors and infectious destruction. However, torque forces necessary for a satisfactory expansion of these implants and for subsidence of them into the adjacent vertebrae are unknown within the osteoporotic spine.

METHODS

Six fresh-frozen human, osteoporotic, lumbar spines were dorsally instrumented with titanium implants (L2-L4) and a partial corpectomy of L3 was performed. An expandable titanium-cage was inserted ventrally and expanded by both residents and senior surgeons until fixation was deemed sufficient, based on haptic feedback. Torque forces for expansion were measured in Nm. Expansion was then continued until cage subsidence occurred. Torque forces necessary for subsidence were recorded. Strain of the dorsal rods during expansion was measured with strain gauges.

FINDINGS

The mean torque force for fixation of cages was 1.17 Nm (0.9 Nm for residents, 1.4 Nm for senior surgeons, p = .06). The mean torque force for subsidence of cages was 3.1 Nm (p = .005). Mean peak strain of the dorsal rods was 970 μm/m during expansion and 1792 μm/m at subsidence of cages (p = .004).

INTERPRETATION

The use of expandable titanium-cages for vertebral body replacement seems to be a primarily safe procedure even within the osteoporotic spine as torque forces required for subsidence of cages are nearly three times higher than those needed for fixation. Most of the expansion load is absorbed by straining of the dorsal instrumentation. Rod materials other than titanium may alter the torque forces found in this study.

Customized 3-dimensional-printed Vertebral Implants for Spinal Reconstruction After Tumor Resection: A Systematic Review

STUDY DESIGN

Systematic review.

OBJECTIVE

To examine the outcomes of customized 3-dimensional (3D) printed implants for spinal reconstruction after tumor resection.

SUMMARY OF BACKGROUND DATA

Various techniques exist for spinal reconstruction after tumor resection. Currently, there is no consensus regarding the utility of customized 3D-printed implants for spinal reconstruction after tumor resection.

MATERIALS AND METHODS

A systematic review was registered with PROSPERO and performed according to "Preferred Reporting Items for Systematic Reviews and Meta-analyses" guidelines. All level I-V evidence studies reporting the use of 3D-printed implants for spinal reconstruction after tumor resection were included.

RESULTS

Eleven studies (65 patients; mean age, 40.9 ± 18.1 y) were included. Eleven patients (16.9%) underwent intralesional resections with positive margins and 54 patients (83.1%) underwent en bloc spondylectomy with negative margins. All patients underwent vertebral reconstruction with 3D-printed titanium implants. Tumor involvement was in the cervical spine in 21 patients (32.3%), thoracic spine in 29 patients (44.6%), thoracolumbar junction in 2 patients (3.1%), and lumbar spine in 13 patients (20.0%). Ten studies with 62 patients reported perioperative outcomes radiologic/oncologic status at final follow-up. At the mean final follow-up of 18.5 ± 9.8 months, 47 patients (75.8%) had no evidence of disease, 9 patients (14.5%) were alive with recurrence, and 6 patients (9.7%) had died of disease. One patient who underwent C3-C5 en bloc spondylectomy had an asymptomatic subsidence of 2.7 mm at the final follow-up. Twenty patients that underwent thoracic and/or lumbar reconstruction had a mean subsidence of 3.8 ± 4.7 mm at the final follow-up; however, only 1 patient had a symptomatic subsidence that required revision surgery. Eleven patients (17.7%) had one or more major complications.

CONCLUSION

There is some evidence to suggest that using customized 3D-printed titanium or titanium alloy implants is an effective technique for spinal reconstruction after tumor resection. There is a high incidence of asymptomatic subsidence and major complications that are similar to other methods of reconstruction.

LEVEL OF EVIDENCE

Level V, systematic review of level I-V studies.

Anterior Column Reconstruction of Destructive Vertebral Osteomyelitis at the Thoracolumbar Spine with an Expandable Vertebral Body Replacement Implant: A Retrospective, Monocentric Radiological Cohort Analysis of 24 Cases

BACKGROUND

Vertebral osteomyelitis (VO) often necessitates surgical intervention due to bone loss-induced spinal instability. Anterior column reconstruction, utilizing expandable vertebral body replacement (VBR) implants, is a recognized approach to restore stability and prevent neurological compromise. Despite various techniques, clinical evidence regarding the safety and efficacy of these implants in VO remains limited.

METHODS

A retrospective cohort analysis, spanning 2000 to 2020, was conducted on 24 destructive VO cases at a Level 1 orthopedic trauma center. Diagnosis relied on clinical, radiological, and microbiological criteria. Patient demographics, clinical presentation, surgical interventions, and radiological outcomes were assessed.

RESULTS

The study included 24 patients (62.5% male; mean age 65.6 ± 35.0 years), with 58% having healthcare-associated infections (HAVO). The mean radiological follow-up was 137.2 ± 161.7 weeks. Surgical intervention significantly improved the bi-segmental kyphotic endplate angle (BKA) postoperatively (mean -1.4° ± 13.6°). However, a noticeable loss of correction was observed over time. The study reported a mortality rate of 1/24.

CONCLUSIONS

Anterior column reconstruction using expandable VBR effectively improved local spinal alignment in destructive VO. However, the study underscores the necessity for prolonged follow-up and continuous research to refine surgical techniques and postoperative care. Addressing long-term complications and refining surgical approaches will be pivotal as the field progresses.

Clinical and radiological outcomes of n-HA/PA66 cages in anterior spine reconstruction following total en bloc spondylectomy for tumors

Objective

This retrospective monocentric study was conducted to evaluate the clinical and radiological outcomes of the nano-hydroxyapatite/polyamide66 (n-HA/PA66) cage in reconstructing the anterior column of the spine following total en bloc spondylectomy (TES).

Methods

A cohort of 24 patients, 20 diagnosed with primary malignant tumors and 4 with metastatic malignancies, was selected based on specific inclusion criteria. All were subjected to TES and anterior column reconstruction with the n-HA/PA66 cage from January 2013 to July 2023 at a single institution. Pre-operative embolization was performed on all patients. Documented factors included operation duration, intraoperative blood loss, length of hospital stay, treatment history, and involved level. Mechanical complications and radiological parameters such as the local kyphotic angle (LKA), anterior vertebral height (AVH), posterior vertebral height (PVH), cage subsidence, and bone fusion time were evaluated. Quality of life and neurological function were gauged using tools like the Visual Analog Scale (VAS), Eastern Cooperative Oncology Group (ECOG) performance score, Karnofsky Performance Score (KPS) scale, and American Spinal Injury Association (ASIA) grading.

Results

All patients were followed up for 12-127 months, with an average period of 39.71 months. An average operation time of approximately 8.57 h and a blood loss volume of about 1,384 ml were recorded. No instances of tumor recurrence or multiple organ metastases were reported, though recurrence was detected in 2 living patients. Solid fusion was achieved in all patients at a mean time of 6.76 ± 0.69 months. Cage breakage or migration was not observed. Subsidence into the adjacent vertebral bodies was identified in 3 patients but was deemed clinically irrelevant. Significant improvements in VAS, ECOG performance score, KPS scale, and ASIA scores were noted from pre- to post-surgery (P < 0.05). A marked enhancement in the AVH was observed from before surgery to immediately after (P < 0.05). LKA, AVH, and PVH values between postoperative and final follow-up showed no significant variance (P > 0.05).

Conclusion

The integration of TES and the n-HA/PA66 cage was found to yield promising clinical and radiological outcomes in anterior column spine reconstruction. The use of this material did not hinder oncological care, including the provision of adjuvant treatments (chemo/radiotherapy), ultimately contributing to the enhanced long-term quality of life for spinal tumor patients.

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

PURPOSE

The 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.

METHODS

Patients 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.

RESULTS

A 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.

CONCLUSIONS

This 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.

Is 3D-printed prosthesis stable and economic enough for anterior spinal column reconstruction after spinal tumor resection? A retrospective comparative study between 3D-printed off-the-shelf prosthesis and titanium mesh cage

OBJECT

To investigate the stability and cost-effectiveness of the three-dimensional-printed (3DP) off-the-shelf (OTS) prosthesis in the reconstruction of the anterior column of the thoracic/lumbar spine after tumor resection.

METHODS

Thirty-five patients (26 with primary malignant tumors and nine with metastatic malignant tumors) who underwent tumor resection and anterior column reconstruction between January 2014 and January 2019 were included in a single institute. Patients were divided into the 3DP OTS prosthesis (3DP) group (n = 14) and the titanium mesh cage (TMC) group (n = 21) by the type of implant. The operation time, intraoperative blood loss, hospital stay, history of radiotherapy, surgical level and total cost were collected and compared between the two groups. Mechanical complications and radiological parameters including mean vertebral height, subsidence, fixation failure(nonunion, migration, screw loosening, rod breakage) rate were recorded at preoperation, 1 week, 3 months, 6 months, 12 months after surgery then at 1 year interval or stop until the end of survival. The follow-up patients were also sent with short form-36 to assess their health-related quality of life (HRQoL) and questions about the current condition of their disease.

RESULTS

The mean overall follow-up was 24.6 months. Of the 35 patients involved, six patients died and six were lost to follow-up. The differences between the two groups in operative time, intraoperative blood loss, and hospital stay were not statistically significant (p > 0.05). The differences in fixation failure and the subsidence rate between the two groups were not statistical significant (p > 0.05). The difference of subsidence rate between the cases with and without osteoporosis, cases with and without radiotherapy was statistically significant within each group (p < 0.05). However, the difference of subsidence rate between the surgical level above or below T10 was not statistically significant (p > 0.05). The response rate of the questionnaire among the survived patients was 100% (23/23 patients). The results of the Short Form- (SF-)36 between the two groups were similar (p > 0.05). The total cost was higher in the 3DP group (p < 0.05) with its higher graft cost (p < 0.05), but the differences in internal fixation cost and other cost were not statistically significant between groups (p > 0.05).

CONCLUSION

Compared to TMC, the 3DP OTS prosthesis achieved similar clinical and radiological results in spinal anterior spinal column reconstruction of thoracic/lumbar spinal tumor resection. However, the 3DP OTS prosthesis was more expansive than TMC.

3D-printed vertebral body for anterior spinal reconstruction in patients with thoracolumbar spinal tumors

OBJECTIVE

A 3D-printed vertebral prosthesis can be used to reconstruct a bone defect more precisely because of its tailored shape, with its innermost porous structure inducing bone ingrowth. The aim of this study was to evaluate the clinical outcomes of using a 3D-printed artificial vertebral body for spinal reconstruction after en bloc resection of thoracolumbar tumors.

METHODS

This was a retrospective analysis of 23 consecutive patients who underwent surgical treatment for thoracolumbar tumors at our hospital. En bloc resection was performed in all cases, based on the Weinstein-Boriani-Biagini surgical staging system, and anterior reconstruction was performed using a 3D-printed artificial vertebral body. Prosthesis subsidence, fusion status, and instrumentation-related complications were evaluated. Stability of the anterior reconstruction method was evaluated by CT, and CT Hounsfield unit (HU) values were measured to evaluate fusion status.

RESULTS

The median follow-up was 37 (range 24-58) months. A customized 3D-printed artificial vertebral body was used in 10 patients, with an off-the-shelf 3D-printed artificial vertebral body used in the other 13 patients. The artificial vertebral body was implanted anteriorly in 5 patients and posteriorly in 18 patients. The overall fusion rate was 87.0%. The average prosthesis subsidence at the final follow-up was 1.60 ± 1.79 mm. Instrument failure occurred in 2 patients, both of whom had substantial subsidence (8.47 and 3.69 mm, respectively). At 3 months, 6 months, and 1 year postoperatively, the mean CT HU values within the artificial vertebral body were 1930 ± 294, 1997 ± 336, and 1994 ± 257, respectively, with each of these values being significantly higher than the immediate postoperative value of 1744 ± 321 (p < 0.05).

CONCLUSIONS

The use of a 3D-printed artificial vertebral body for anterior reconstruction after en bloc resection of the thoracolumbar spinal tumor may be a feasible and reliable option. The low incidence of prosthesis subsidence of 3D-printed endoprostheses can provide good stability instantly. Measurement of HU values with CT is a valuable method to evaluate the osseointegration at the bone-metal interface of a 3D-printed vertebral prosthesis.

Preliminary Results of a 3D-Printed Modular Vertebral Prosthesis for Anterior Column Reconstruction after Multilevel Thoracolumbar Total En Bloc Spondylectomy

OBJECTIVE

To evaluate preliminary results of a 3D-printed modular prosthesis for spinal reconstruction after multilevel thoracolumbar total en bloc spondylectomy (TES).

METHODS

Patients with thoracolumbar spinal tumors treated surgically between January 2016 and April 2019 were included in this retrospective study. A total of 17 male and 10 female patients with a mean age of 42 (range, 15-72) years comprised the sample. The pathological diagnoses included six chondrosarcomas (one of them was mesenchymal chondrosarcoma), six giant cell tumors, three malignant peripheral nerve sheath tumors, two osteosarcomas, two undifferentiated high-grade pleomorphic sarcomas (UPS), two solitary fibrous tumors, one Ewing's sarcoma, one liposarcoma, and four metastatic tumors. Tumors involved 2 levels in 14 patients, 3 levels in seven patients, 4 levels in four patients, 5 levels in one patient, and 6 levels in one patient. A 3D-printed modular prosthesis was used for anterior column reconstruction after TES. All analyses were performed using SPSS version 18.0 (SPSS, Inc., Chicago, IL). Descriptive statistics were used to analyze the demographic data and clinical outcomes. Data forms included mean, standard deviation and range.

RESULTS

Under general anesthesia, all patients received TES with an average operative time of 639 (range, 210-1650) min, and the mean blood loss during operation was 4.1 (range, 0.8-13.3) L. Twenty-two patients have been transferred to ICU for a mean time of 3.2 (range, 0-6) d. All patients had follow-up procedures except for one, who died of perioperative complications. Mean time of follow-up was 22 (range, 12-41) months. Local recurrence (19.2%) occurred in two patients with intralesional margin and three patients with marginal margin, respectively. At the end of follow-up, three patients died of disease, eight patients were alive with disease, and 15 patients had no evidence of disease. Average lengths of resected vertebrae and modular prostheses were 71.4 ± 26.5 mm (range, 40-142 mm) and 68.4 ± 23.9 mm (range, 40-132 mm), respectively. In 26 patients with minimum follow-up of more than 1 year, no evidence of internal fixation failure or dislocation of vertebral prosthesis was found. Asymptomatic prosthetic subsidence into adjacent vertebral bodies occurred in 10 patients with a mean length of 1.8 ± 1.0 mm (range, 1-4 mm). The subsidence was seen at proximal end in two patients, distal end in four patients, and both ends in four patients. Eighteen major complications and 14 minor complications were found in 15 patients. All patients fully recovered at 3 or 6 months after operation. At the latest follow-up, in 23 alive patients, 19 can walk independently and two can achieve outdoor activities by walking aid.

CONCLUSION

For spinal reconstruction after multilevel thoracolumbar TES, 3D-printed modular vertebral prosthesis is suitable for different length of anterior column reconstruction with less mechanical complications, and can provide a stable environment to maintain or rehabilitate patients' neurological function in short-term follow-up.

Application of an Expandable Cage for Reconstruction of the Cervical Spine in a Consecutive Series of Eighty-Six Patients

Background and objectives: Expandable cages are frequently used to reconstruct the anterior spinal column after a corpectomy. In this retrospective study, we evaluated the perioperative advantages and disadvantages of corpectomy reconstruction with an expandable cage. Materials and Methods: Eighty-six patients (45 male and 41 female patients, medium age of 61.3 years) were treated with an expandable titanium cage for a variety of indications from January 2012 to December 2019 and analyzed retrospectively. The mean follow-up was 30.7 months. Outcome was measured by clinical examination and visual analogue scale (VAS); myelopathy was classified according to the EMS (European Myelopathy Scale) and gait disturbances with the Nurick score. Radiographic analysis comprised measurement of fusion, subsidence and the C2–C7 angle. Results: Indications included spinal canal stenosis with myelopathy (46 or 53.5%), metastasis (24 or 27.9%), spondylodiscitis (12 or 14%), and fracture (4 or 4.6%). In 39 patients (45.3%), additional dorsal stabilization (360° fusion) was performed. In 13 patients, hardware failure occurred, and in 8 patients, adjacent segment disease occurred. Improvement of pain symptoms, myelopathy, and gait following surgery were statistically significant (p < 0.05), with a medium preoperative VAS of 8, a postoperative score of 3.2, and medium EMS scores of 11.3 preoperatively vs. 14.3 postoperatively. Radiographic analysis showed successful fusion in 74 patients (86%). As shown in previous studies, correction of the C2–C7 angle did not correlate with improvement of neurological symptoms. Conclusion: Our results show that expandable titanium cages are a safe and useful tool in anterior cervical corpectomies for providing adequate anterior column support and stability.

Evaluation of the effectiveness of expandable cages for reconstruction of the anterior column of the spine

PURPOSE

For anterior spine column reconstruction after corpectomy, expandable cages offer solid anterior support and allow correction of deformity, providing excellent primary stability. To provide a larger body of clinical observations concerning the effectiveness of the approach, this retrospective study examines patients treated by corpectomy and reconstruction with an expandable cage for different pathologies.

METHODS

Across 5 years, 39 patients underwent vertebral reconstruction with expandable cages after single (n = 34), double (n = 4), or triple (n = 1) corpectomy. Pathologies were tumors (n = 21), fractures, or deformities in traumatic injuries (n = 14), degenerative pathology (n = 2), and infection (n = 2). Levels were cervical (n = 10), thoracic (n = 14), and lumbar (n = 15). All patients were evaluated clinically and radiographically.

RESULTS

There were no cases of neurologic deterioration. Nurick grade showed significant improvement at 3 months postoperative versus preoperative (p < 0.01). Visual analog scale significantly improved preoperatively versus 3 and 12 months postoperatively (both p = 0). Regional angulation was significantly corrected, from preoperative to 3 and 12 months postoperative, at cervical, thoracic, and lumbar levels. We achieved reconstruction of the normal local anatomy with full recovery of the height of the vertebral body. Six patients (15.4%) had complications and two (5.1%) underwent revision surgery.

CONCLUSIONS

In our experience, expandable cages confer stable anterior support, providing significant improvement of the segmental kyphosis angle and restoration of the original somatic height. Our clinical results are favorable, and the low rate of complications and revision accentuates the expandable cage as a valuable tool to replace the vertebral body in diverse pathologies and different spine levels.

In vitro comparison of personalized 3D printed versus standard expandable titanium vertebral body replacement implants in the mid-thoracic spine using entire rib cage specimens

BACKGROUND

Expandable titanium implants have proven their suitability as vertebral body replacement device in several clinical and biomechanical studies. Potential stabilizing features of personalized 3D printed titanium devices, however, have never been explored. This in vitro study aimed to prove their equivalence regarding primary stability and three-dimensional motion behavior in the mid-thoracic spine including the entire rib cage.

METHODS

Six fresh frozen human thoracic spine specimens with intact rib cages were loaded with pure moments of 5 Nm while performing optical motion tracking of all vertebrae. Following testing in intact condition (1), the specimens were tested after inserting personalized 3D printed titanium vertebral body replacement implants (2) and the two standard expandable titanium implants Obelisc™ (3) and Synex™ (4), each at T6 level combined with posterior pedicle screw-rod fixation from T4 to T8.

FINDINGS

No significant differences (P < .05) in primary and secondary T1-T12 ranges of motion were found between the three implant types. Compared to the intact condition, slight decreases of the range of motion were found, which were significant for Synex™ in primary flexion/extension (-17%), specifically at T3-T4 level (-46%), primary lateral bending (-18%), and secondary lateral bending during primary axial rotation (-53%). Range of motion solely increased at T8-T9 level, while being significant only for Obelisc™ (+35%).

INTERPRETATION

Personalized 3D printed vertebral body replacement implants provide a promising alternative to standard expandable devices regarding primary stability and three-dimensional motion behavior in the mid-thoracic spine due to the stabilizing effect of the rib cage.

Implants for Vertebral Body Replacement - Which Systems are Available and Have Become Established

Since the first vertebral body replacement operations over 50 years ago until now, there were developed numerous methods and implants. Vertebral body replacement after corpectomy nowadays is a standard procedure in spinal surgery. At the beginning mainly bone grafts were used. Due to continuous development, PMMA and titanium implants were developed. Nowadays various expandable and non-expandable implants are available. Numerous implants can still be justified. The question arises which methods and systems are on the market and which ones have proven themselves? This article describes and compares the advantages and disadvantages of each implant type.

Three-Level Lumbar En Bloc Spondylectomy with Three-Dimensional-Printed Vertebrae Reconstruction for Recurrent Giant Cell Tumor

BACKGROUND

Primary malignancies involving the mobile spine often require total en bloc spondylectomy with complex mechanical reconstruction, which can be augmented with novel application of the 3-dimensional (3D)-printing technique.

CASE DESCRIPTION

A 51-year-old man presented with a 12-month history of progressive thigh pain and lower limb motor function loss, 36 months after T12-L4 instrumentation and fusion for giant cell tumor (GCT) of the L2 vertebrae before referral. The patient subsequently underwent successful curative management of recurrent GCT through denosumab treatment, L1-L3 total en bloc spondylectomy (TES), and a novel lumbopelvic reconstruction method with a 3D-printed lumbar vertebrae and screw-rod system.

CONCLUSIONS

To our knowledge, this is the first reported case of multilevel lumbar TES for GCT reconstructed using a 3D-printed vertebrae. Although TES-specifically in the lumbosacral spine-remains challenging due to its unique anatomy and increased risk of neurologic insult, it is an effective option for curative management of GCTs.

Palliative Posterior Instrumentation versus Corpectomy with Cage Reconstruction Treatment for Thoracolumbar Pathological Fracture

Study Design

Single-center, retrospective cohort study.

Purpose

We aimed to evaluate and compare the clinical outcomes in patients who underwent palliative posterior instrumentation (PPI) versus those who underwent corpectomy with cage reconstruction (CCR) for thoracolumbar pathological fracture.

Overview of Literature

The requirement for anterior support after corpectomy has been emphasized in the treatment of pathological fractures of the vertebrae. However, for patients with a relatively short life expectancy, anterior reconstruction may not be required and posterior instrumentation alone may provide adequate stabilization.

Methods

A total of 43 patients with metastases of the thoracolumbar spine underwent surgery in the department of orthopaedic and traumatology of Istanbul University Faculty of Medicine from 2003 to 2016. Surgical outcomes were assessed on the basis of survival status, pre- and postoperative pain, complication rate, and operation time.

Results

PPI was performed for 22 patients and CCR was performed for 21 patients. In the PPI group, the follow-up period of the five surviving patients was 32 months. The remaining 17 patients died with a mean survival duration of 12.3 months postoperatively. In the CCR group, the five surviving patients were followed up for an average of 14.1 months. The remaining 16 patients died with a mean survival duration of 18.7 months postoperatively. No statistically significant difference (p=0.812) was noted in the survival duration. The Visual Analog Scale scores of the patients were significantly reduced after both procedures, with no significant difference noted on the basis of the type of surgical intervention (p>0.05). The complication rate in the CCR group (33.3%) was higher compared with that in the PPI group (22.7%); however, this difference was not noted to be statistically significant (p=0.379). The average operation time in the PPI group (149 minutes) was significantly shorter (p=0.04) than that in the CCR group (192 minutes).

Conclusions

The PPI technique can decompress the tumor for functional improvement and can stabilize the spinal structure to provide pain relief.

Biomimetic 3D-printed custom-made prosthesis for anterior column reconstruction in the thoracolumbar spine: a tailored option following en bloc resection for spinal tumors : Preliminary results on a case-series of 13 patients

PURPOSE

Various techniques for anterior column reconstruction have been described after en bloc resection of spinal tumors. Limited evidence exists regarding one being superior to another. The purpose of this study is to evaluate 3D-printed vertebral bodies for spinal reconstruction after en bloc resection in the thoracolumbar spine.

METHODS

Prospective observational study on custom-made 3D-printed titanium reconstruction of vertebral bodies after en bloc resection for spinal tumor was conducted between November 2015 and June 2017. 3D-printed vertebral bodies were monitored for mechanical complications such as (1) migration, (2) subsidence into the adjacent vertebral bodies, and/or (3) breakage. Complications and related details were recorded.

RESULTS

Thirteen patients (7 females and 6 males) were enrolled, and reconstruction of the anterior column was performed using custom-made 3D-printed titanium prosthesis after en bloc resection for spinal tumor (8 primary bone tumors and 5 solitary metastases). Subsidence into the adjacent vertebral bodies occurred in all patients at both proximal and distal bone-implant interfaces; however, it was clinically irrelevant (asymptomatic, and no consequences on posterior instrumentation), in 11 out of 12 patients (92%). In 1 patient (#4), severity of the subsidence led to revision of the construct. At an average 10-month follow-up (range 2-16), 1 implant was removed due to local recurrence of the disease and 1 was revisioned due to progressive distal junctional kyphosis.

CONCLUSION

Preliminary results from this series suggest that 3D printing can be effectively used to produce custom-made prosthesis for anterior column reconstruction. These slides can be retrieved under Electronic Supplementary Material.

Interbody distraction and vertebral body reconstruction with polymethylmethacrylate for the treatment of pathological fractures

OBJECTIVE Treatment of epidural spinal cord compression (ESCC) caused by tumor includes surgical decompression and stabilization followed by postoperative radiation. In the case of severe axial loading impairment, anterior column reconstruction is indicated. The authors describe the use of interbody distraction to restore vertebral body height and correct kyphotic angulation prior to reconstruction with polymethylmethacrylate (PMMA), and report the long-term durability of such reconstruction. METHODS A single institution, prospective series of patients with ESCC undergoing single-stage decompression, anterior column reconstruction, and posterior instrumentation from 2013 to 2016 was retrospectively analyzed. Several demographic, perioperative, and radiographic measurements were collected. Descriptive statistics were compiled, in addition to postoperative changes in anterior height, posterior height, and kyphosis. Paired Student t-tests were performed for each variable. Overall survival was calculated using the techniques described by Kaplan and Meier. RESULTS Twenty-one patients underwent single-stage posterior decompression with interbody distraction and anterior column reconstruction using PMMA. The median age and Karnofsky Performance Scale score were 61 years and 70, respectively. Primary tumors included renal cell (n = 8), lung (n = 4), multiple myeloma (n = 2), prostate (n = 2), and other (n = 5). Eighteen patients underwent a single-level vertebral body reconstruction and 3 underwent multilevel transpedicular corpectomies. The median survival duration was 13.3 months. In the immediate postoperative setting, statistically significant improvement was noted in anterior body height (p = 0.0017, 95% confidence interval [CI] -4.15 to -1.11) and posterior body height (p = 0.0116, 95% CI -3.14 to -0.45) in all patients, and improved kyphosis was observed in those with oblique endplates (p = 0.0002, 95% CI 11.16-20.27). In the median follow-up duration of 13.9 months, the authors observed 3 cases of asymptomatic PMMA subsidence. One patient required reoperation in the form of extension of fusion. CONCLUSIONS In situ interbody distraction allows safe and durable reconstruction with PMMA, restores vertebral height, and corrects kyphotic deformities associated with severe pathological fractures caused by tumor. This is accomplished with minimal manipulation of the thecal sac and avoiding an extensive 360° surgical approach in patients who cannot tolerate extensive surgery.

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.

Changing the Adverse Event Profile in Metastatic Spine Surgery: An Evidence-Based Approach to Target Wound Complications and Instrumentation Failure

STUDY DESIGN

Systematic review.

OBJECTIVE

To identify risk factors and preventive methods for wound complications and instrumentation failure after metastatic spine surgery.

SUMMARY OF BACKGROUND DATA

We focused on two postoperative complications of metastatic spine tumor surgery: wound complications and instrumentation failure and preventive measures.

METHODS

We performed a systematic review of the literature from 1980 to 2015. The articles were analyzed for the presence of documented infection and/or wound complications and instrumentation failure.

RESULTS

Forty articles met our inclusion criteria for wound complications and prevention. There is very low level of evidence that preoperative radiation, preoperative neurological deficit, revision procedures, and posterior approaches can contribute to wound complications (infections, wound dehiscence). There is very low level of evidence that plastic surgery soft tissue reconstruction, intrawound vancomycin powder, and percutaneous pedicle screws may prevent postoperative wound complications. Fourteen articles met our inclusion criteria for instrumentation failure. There is very low level of evidence that constructs greater than six levels, positive sagittal balance, preoperative radiation, and history of chest wall resection can contribute to implant failures.

CONCLUSION

• For patients undergoing revision metastatic spine tumor surgery, plastic surgery should perform the soft tissue reconstruction (strong recommendation/very low quality of evidence).• For patients undergoing metastatic spine tumor surgery, plastic surgery may perform immediate soft tissue reconstruction (weak recommendation/very low quality of evidence).• For patients undergoing metastatic spine tumor surgery, intrawound vancomycin can be applied to decrease the risk of postoperative wound infections (weak recommendation/very low quality of evidence).• For patients undergoing metastatic spine tumor surgery, percutaneous pedicle screws can be placed to decrease the risk of postoperative wound complications (weak recommendation/very low quality of evidence).• Instrumentation failure risk factors include constructs greater than six levels, positive sagittal balance, preoperative radiation, and history of chest wall resections (weak recommendation/very low quality of evidence).

LEVEL OF EVIDENCE

N/A.

Posterior-Only Circumferential Decompression and Reconstruction in the Surgical Management of Lumbar Vertebral Osteomyelitis

Study Design Case report. Objective The purpose of this report is to discuss the surgical management of lumbar vertebral osteomyelitis with a spinal epidural abscess (SEA) and present a single-stage, posterior-only circumferential decompression and reconstruction with instrumentation using an expandable titanium cage and without segmental nerve root sacrifice as an option in the treatment of this disease process. Methods We report a 42-year-old man who presented with 3 days of low back pain and chills who rapidly decompensated with severe sepsis following admission. Magnetic resonance imaging of his lumbosacral spine revealed intramuscular abscesses of the left paraspinal musculature and iliopsoas with SEA and L4 vertebral body involvement. The patient failed maximal medical treatment, which necessitated surgical treatment as a last resort for infectious source control. He underwent a previously undescribed procedure in the setting of SEA: a single-stage, posterior-only approach for circumferential decompression and reconstruction of the L4 vertebral body with posterior segmental instrumented fixation. Results After the surgery, the patient's condition gradually improved; however, he suffered a wound dehiscence necessitating a surgical exploration and deep wound debridement. Six months after the surgery, the patient underwent a revision surgery for adjacent-level pseudarthrosis. At 1-year follow-up, the patient was pain-free and off narcotic pain medication and had returned to full activity. Conclusion This patient is the first reported case of lumbar osteomyelitis with SEA treated surgically with a single-stage, posterior-only circumferential decompression and reconstruction with posterior instrumentation. Although this approach is more technically challenging, it presents another viable option for the treatment of lumbar vertebral osteomyelitis that may reduce the morbidity associated with an anterior approach.

Palliative transpedicular partial corpectomy without anterior vertebral reconstruction in lower thoracic and thoracolumbar junction spinal metastases

Background

The thoracolumbar junction is the transition from a stiff (thoracic spine) to a mobile zone (lumbar spine) and is relatively unstable compared with the thoracic and lumbar portions of the spine. The need for anterior reconstruction after a corpectomy has been emphasized by several authors. However, for patients with a relatively short life expectancy, anterior reconstruction may be unnecessary. Posterior instrumentation alone may be sufficient to provide pain relief and stability for such patients. The goal of this study was to assess the postoperative outcomes and survival rates of patients with tumor metastases of the lower thoracic spine and thoracolumbar junction (T10–L1) who underwent transpedicular partial corpectomy without anterior vertebral reconstruction.

Methods

From November 2001 to February 2015, 29 patients diagnosed with symptomatic spinal cord compression caused by tumor metastasis involving T10 to L1 underwent palliative surgery that involved a posterolateral transpedicular partial corpectomy without anterior reconstruction. The surgical indication was neurologic progression. A follow-up was conducted for all of the patients, including reviewing medical records and performing an examination in the outpatient department.

Results

The patients ranged in age from 33 to 83 years (mean, 61.6 years). Neurologic improvement by at least one Frankel grade was noted in 75.9 % of the patients (N = 22). Neither intraoperative mortality nor implant failure was reported. The median survival rate was 7.43 months (range, 0.47–28 months).

Conclusion

The results of this study suggest that the stability of implants can be maintained up to 28 months with satisfying functional outcome after a palliative posterolateral transpedicular partial corpectomy without anterior reconstruction.

Vertebral body replacement by posterior approach for metastatic disease in the thoracic spine--modified technique using an expandable cage

OBJECTIVE

To describe the technique of all-posterior vertebral body replacement using an expandable cage and angled instruments. This method facilitates implant seating with limited posterior decompression useful in the setting of metastatic disease.

INDICATIONS

Patients with metastatic disease of the thoracic spine with or without spinal cord compression.

CONTRAINDICATIONS

Patients with a limited life expectancy of less than 6 months. Multiple foci of metastatic disease in the spine.

SURGICAL TECHNIQUE

A hemilaminectomy was performed followed by nerve root sacrifice. The pleura was mobilized away from the vertebral body, after which decompression and tumor resection was performed from an all-posterior approach. An expandable vertebral body cage was inserted with a rotational manoeuvre and expanded in situ.

POSTOPERATIVE MANAGEMENT

The patient was mobilized on postoperative day 1. A chest X-ray is also recommended to exclude incidental pneumothorax.

RESULTS

Four patients were operated by an all-posterior vertebral body replacement during a 6-month period. The average length of surgical procedure was 187 min (range 165-220 min). No patient required a transthoracic approach. There were no intra- or postoperative complications and all patients could be discharged to home self-ambulating.

Reconstruction with expandable cages after single- and multilevel corpectomies for spinal metastases: a prospective case series of 60 patients

BACKGROUND CONTEXT

Expandable cages are widely used to reconstruct the spine after the removal of vertebral metastases. Long-term results, however, are lacking, and there is little information on reconstruction after multilevel corpectomies.

PURPOSE

To determine long-term outcome for reconstruction of the spine with expandable cages after single and multilevel corpectomies for spinal metastases.

STUDY DESIGN

A prospective cohort study of 60 consecutive patients with spinal metastases treated with expandable cages.

METHODS

All patients were prospectively followed with regular clinical and radiographic evaluation. Outcome measures were the Frankel score, patients' self-reported recovery, radiological alignment of the spine, and neurologic plus biomechanical complications.

RESULTS

Sixty patients were treated with expandable cages in our hospital in a 5-year period with a maximum follow-up of 6 years. Single-level reconstruction was performed in 48 cases, 2-level in 8, and 3-level in 4. Postoperatively, the Frankel score had improved significantly (p=.03), the segment height had increased (p=.02), and, in severe cases of kyphosis (>20°), the regional angulation had been corrected compared with preoperatively (p<.001). Complication rate, however, was high (36.7%), in particular after multilevel reconstruction, in which three cases had to be reoperated years after the initial surgery; reasons for this were hardware failure, progressive kyphosis, and bronchial perforation. Good recovery was reported in 70% of all patients.

CONCLUSIONS

Expandable cages can be used successfully in reconstruction of the spine after single and multilevel corpectomies for spinal metastases. However, long-term complication rate is high. Promotion of bony fusion, prevention of soft-tissue damage, adequate posterior stabilization, and careful patient selection may reduce these complications.

Optimal approach to circumferential decompression and reconstruction for thoracic spine metastatic disease

BACKGROUND

Circumferential decompression has been demonstrated to be the first-line therapy for patients with metastatic tumors in the thoracic spine requiring surgical intervention. However, there is significant debate regarding whether these tumors are best accessed anteriorly utilizing a thoracotomy or posteriorly. We used decision analysis to determine which approach yields greater health-related quality of life (QOL).

METHODS

We searched Medline, Embase, and the Cochrane Library for relevant articles published between 1990 and 2011 on anterior and posterior approaches to metastatic disease in the thoracic spine. QOL values for major treatment outcomes were determined using the existing literature. Separate models were created for ambulatory and nonambulatory patients. A Monte Carlo simulation and sensitivity analyses were used to determine which treatment strategy resulted in the highest QOL.

RESULTS

For ambulatory patients, an anterior approach resulted in a slightly higher QOL, and for nonambulatory patients, a posterior approach was favored, but these differences were not statistically significant.

CONCLUSIONS

Using a decision-analytic model, we found no significant difference in QOL resulting from anterior versus posterior approaches to metastatic lesions in the thoracic spine. Decisions should instead be based on surgeon comfort, tumor characteristics, anatomy of the lesion, patient-related factors, and goals of the operation.

Radiological outcomes of static vs expandable titanium cages after corpectomy: a retrospective cohort analysis of subsidence

BACKGROUND

Mesh cages have commonly been used for reconstruction after corpectomy. Recently, expandable cages have become a popular alternative. Regardless of cage type, subsidence is a concern following cage placement.

OBJECTIVE

To assess whether subsidence rates differ between static and expandable cages, and identify independent risk factors for subsidence and extent of subsidence when present.

METHODS

A consecutive population of patients who underwent corpectomy between 2006 and 2009 was identified. Subsidence was assessed via x-ray at 1-month and 1-year follow-ups. In addition to cage type, demographic, medical, and cage-related covariates were recorded. Multivariate models were used to assess independent associations with rate, odds, and extent of subsidence.

RESULTS

Of 91 patients, 44.0% had expandable cages and 56.0% had static cages. One-month subsidence rate was 36.3%, and the 1-year subsidence rate was 51.6%. Expandable cages were independently associated with higher rates and odds of subsidence in comparison with static cages. Infection, trauma, and footplate-to-vertebral body endplate ratio of less than 0.5 were independent risk factors for subsidence. The presence of prongs on cages and posterior fusion 2 or more levels above and below corpectomy level had lower rates and odds of subsidence. Infection and cage placement in the thoracic or lumbar region had greater extent of subsidence when subsidence was present.

CONCLUSION

Expandable cages had higher rates and risk of subsidence in comparison with static cages. When subsidence was present, expandable cages had greater magnitudes of subsidence. Other factors including footplate-to-vertebral body endplate ratio, prongs, extent of supplemental posterior fusion, spinal region, and diagnosis also impacted subsidence.