The Effect of Spinal Shortening After Total En Bloc Spondylectomy: A Biomechanical Study in the Thoracic Spine

A Systematic Review of Perioperative Complications in en Bloc Resection for Spinal Tumors

STUDY DESIGN

Systematic review.

OBJECTIVE

En bloc resection is a major, invasive surgical procedure designed to completely resect a vertebral tumor with a sufficient margin. It is technically demanding and potentially poses risks of perioperative complications. In this systematic review, we investigated the incidence of complications after en bloc resection for spinal tumors.

METHODS

We screened PubMed and Embase databases for relevant English publications, from 1980 to 2020, using the following terms: spine OR spinal AND en bloc AND tumor. Using a standard PRISMA template, after the initial screening, full-text articles of interest were evaluated.

RESULTS

Thirty-six studies with 961 patients were included. The overall mean age of patients was 49.6 years, and the mean follow-up time was 33.5 months. There were 560 complications, and an overall complication rate of 58.3% (560/961). The 5 most frequent complications were neurological damage (12.7%), hardware failure (12.1%), dural tear and cerebrospinal fluid leakage (10.6%), wound-related complications (7.6%) and vascular injury and bleeding (7.3%). The complication-related revision rate was 10.7% (103/961). The average incidence of complication-related death was 1.2% (12/961).

CONCLUSIONS

En bloc resection is a surgical procedure that is very invasive and technically challenging, and the possible risks of perioperative complications should not be neglected. The overall complication rate is high. However, complication-related death was rare. The advantages of surgery should be weighed against the serious perioperative morbidity associated with this technique.

Characteristics and risk factors of instrumentation failure following total en bloc spondylectomy

AIMS

The aim of this study was to investigate the incidence and characteristics of instrumentation failure (IF) after total en bloc spondylectomy (TES), and to analyze risk factors for IF.

METHODS

The medical records from 136 patients (65 male, 71 female) with a mean age of 52.7 years (14 to 80) who underwent TES were retrospectively reviewed. The mean follow-up period was 101 months (36 to 232). Analyzed factors included incidence of IF, age, sex, BMI, history of chemotherapy or radiotherapy, tumour histology (primary or metastasis; benign or malignant), surgical approach (posterior or combined), tumour location (thoracic or lumbar; junctional or non-junctional), number of resected vertebrae (single or multilevel), anterior resection line (disc-to-disc or intravertebra), type of bone graft (autograft or frozen autograft), cage subsidence (CS), and local alignment (LA). A survival analysis of the instrumentation was performed, and relationships between IF and other factors were investigated using the Cox regression model.

RESULTS

A total of 44 patients (32.4%) developed IF at a median of 31 months (interquartile range 23 to 74) following TES. Most IFs were rod fractures preceded by a mean CS of 6.1 mm (2 to 18) and LA kyphotic enhancement of 10.8° (-1 to 36). IF-free survival rates were 75.8% at five years and 56.9% at ten years. The interval from TES to IF peaked at two to three years postoperatively and continued to occur over a period of time thereafter; the early IF-developing group had greater CS at one month postoperatively (CS1M) and more lumbar TES. CS1M ≥ 3 mm and sole use of frozen autografts were identified as independent risk factors for IF.

CONCLUSION

IF is a common complication following TES. We have demonstrated that robust spinal reconstruction preventing CS, and high-quality bone grafting are necessary for successful reconstruction.Cite this article: Bone Joint J 2023;105-B(2):172-179.

[Guideline-conform treatment of injuries to the subaxial cervical spine]

Injuries to the subaxial cervical spine are increasing and have an increased neurological risk compared to the thoracic and lumbar spines. The current treatment recommendations according to the therapeutic recommendations of the Spine Section of the German Society for Orthopedics and Trauma Surgery (DGOU) as well as the S1 guidelines of the German Trauma Society (DGU) are presented. This second part of the article describes the correct indications and treatment planning for injuries to the cervical spine. Based on the AOSpine classification for subaxial cervical spine injuries, decisions can be made about conservative or surgical treatment as well as individual details of the treatment. The underlying principles of treatment are relief of neurological structures, restoration of stability and reconstruction/preservation of the physiological alignment.

Perioperative complications of total en bloc spondylectomy for spinal tumours

AIMS

To evaluate the perioperative complications associated with total en bloc spondylectomy (TES) in patients with spinal tumours, based on the extent and level of tumour resection.

METHODS

In total, 307 patients who underwent TES in a single centre were reviewed retrospectively. There were 164 male and 143 female patients with a mean age at the time of surgery of 52.9 years (SD 13.3). A total of 225 patients were operated on for spinal metastases, 34 for a malignant primary tumour, 41 for an aggressive benign tumour, and seven with a primary of unknown origin. The main lesion was located in the thoracic spine in 213, and in the lumbar spine in 94 patients. There were 97 patients who underwent TES for more than two consecutive vertebrae.

RESULTS

Major and minor perioperative complications were observed in 122 (39.7%) and 84 (27.4%) patients respectively. The breakdown of complications was as follows: bleeding more than 2,000 ml in 60 (19.5%) patients, hardware failure in 82 (26.7%), neurological in 46 (15.0%), surgical site infection in 23 (7.5%), wound dehiscence in 16 (5.2%), cerebrospinal fluid leakage in 45 (14.7%), respiratory in 52 (16.9%), cardiovascular in 11 (3.6%), digestive in 19 (6.2%)/ The mortality within two months of surgery was four (1.3%). The total number of complications per operation were 1.01 (SD 1.0) in the single vertebral resection group and 1.56 (SD 1.2) in the group with more than two vertebral resections. Cardiovascular and respiratory complications, along with hardware failure were statistically higher in the group who had more than two vertebrae resected. Also, in this group the amount of bleeding in patients with a lumbar lesion or respiratory complication in patients with a thoracic lesion, were statistically higher. Multivariate analysis showed that using a combined anterior and posterior approach, when more than two vertebral resections were significant independent factors.

CONCLUSION

The characteristics of perioperative complications after TES were different depending on the extent and level of the tumour resection. In addition to preoperative clinical and pathological factors, it is therefore important to consider these factors in patients who undergo en bloc resection for spinal tumours. Cite this article: Bone Joint J 2021;103-B(5):976-983.

Rod fracture and related factors after total en bloc spondylectomy

BACKGROUND CONTEXT

Several studies have reported favorable oncosurgical outcomes after total en bloc spondylectomy (TES) for treatment of primary malignant tumors or oligometastatic tumors. Considering that TES is indicated for patients with longer life expectancy, long-term instrumentation-related issues such as rod fracture needs to be addressed.

PURPOSE

To investigate delayed rod fracture and related factors after TES.

STUDY DESIGN

Multicenter, retrospective study.

PATIENT SAMPLE

Thirty-two patients who survived for more than 2 years after TES.

OUTCOME MEASURES

Rod fracture and related factors.

METHODS

The relationships between rod fracture and related factors were investigated using Kaplan-Meier survivorship analysis with log-rank test. The analyzed factors were sex, age (<60 or ≥60), tumor histology (primary or metastatic), location of resected tumor (thoracic [above T11], thoracolumbar [cases including T12-L1], or lumbar [below L2]), number of resected vertebrae (1, 2, or 3), anterior support method (expandable cage, mesh cage, or strut bone graft), rod diameter (5.5 mm or 6.0 mm), and history of radiotherapy including preoperative or postoperative radiotherapy.

RESULTS

The study population consisted of 18 men and 14 women, with a mean age of 49.0 years. Nineteen patients had primary tumors and 13 patients had metastatic tumors. The mean follow-up duration was 49.8 months (range, 24-166 months). Twelve of 32 patients (37.5%) experienced rod fractures at an average of 29.2 months (range, 8-93 months) after TES. Of these 12 patients, 8 underwent revision surgery caused by back pain aggravation (n = 7) or nonunion on computed tomography scan (n = 4). Location of resected tumor and history of radiotherapy were significantly associated with rod fracture (p = .004 and p = .019, respectively).

CONCLUSION

Rod fracture was not a rare complication after TES surgery. History of radiotherapy and TES at lumbar level were significant risk factors related to rod fracture. A robust strategy to obtain solid osseous fusion should be considered when planning TES.

Intraosseous Malignant Peripheral Nerve Sheath Tumor of 2 Consecutive Lumbar Vertebrae: A Case Report and Literature Review

BACKGROUND

Malignant peripheral nerve sheath tumor (MPNST), which refers to any malignant tumor that originates from peripheral nerve sheath cells, is rarely found in the spine. Primary intraosseous spinal MPNSTs are extremely uncommon; in fact, such an occurrence has been reported in a very limited number of cases hitherto. We report here one case of low-grade intraosseous MPNST in the lumbar vertebrae and review clinical research related to this rare tumor and modus operandi to its treatment.

CASE DESCRIPTION

A 51-year-old man suffering from lower back pain was initially diagnosed with lumbar tuberculosis. The intraoperative histopathologic examination, however, revealed that the occupying lesion was synovial sarcoma when surgeons intended to perform a debridement surgery of what was thought to be tuberculosis. The operation was therefore suspended. Two months later, the patient was referred to our institution. The pathologic sections were reexamined. Its results refuted the earlier thought of being synovial sarcoma, and a final diagnosis of MPNST was made. In addition, preoperative examination revealed that the tumor had advanced rapidly to the adjacent inferior vena cava and pedicle, which ruled out the possibility of performing a total en bloc spondylectomy. Therefore, a marginal resection for 2-level consecutive lumbar vertebrae was performed successfully via an anterior-posterior combined approach. No serious complications were detected at 18-month follow-up.

CONCLUSIONS

Preoperative biopsy is of great importance for the diagnosis of spinal tumors. Marginal resection of a complicated intraosseous spine MPNST via an anterior-posterior combined approach, despite being technically challenging, resulted in good survival and functional outcomes.

En bloc vertebrectomy for the treatment of spinal lesions. Five years of experience in a single institution: a case series

OBJECTIVES

The objective of this study is to describe the experience of a Brazilian public university hospital regarding the treatment of metastatic or benign spine lesions with en bloc vertebrectomy of the thoracic and lumbar spines.

METHODS

This study was a retrospective case series and included all medical records of patients with benign aggressive, primary malignant, or metastatic spine lesions who underwent en bloc vertebrectomy from 2010 to 2015.

RESULTS

A total of 17 patients were included in the analysis. Most of them (71%) were indicated for surgery based on an oncologic resection for localized disease cure. Overall, 10 of the 17 patients (59%) underwent vertebrectomy via an isolated posterior approach using the technique described by Roy-Camille et al. and Tomita et al., while 7 patients (41%) underwent double approach surgeries. Of the 17 patients who underwent the en bloc resection, 8 are still alive and in the outpatient follow-up (47%), and almost all patients with metastatic lesions (8/9) died. The average survival time following the surgical procedure was 23.8 months. Considering the cases of metastatic lesions and the cases of localized disease (malignant or benign aggressive disease) separately, we observed an average survival time of 15 months and 47.6 months respectively.

CONCLUSION

This study demonstrates and reinforces the reproducibility of the en bloc vertebrectomy technique described by Tomita et al.

Risk factors of instrumentation failure after multilevel total en bloc spondylectomy

INTRODUCTION

Multilevel total en bloc spondylectomy (TES) is required to secure oncologically adequate resection margins. However, no useful information has been reported for spinal reconstruction after multilevel TES. Therefore, this study set out to assess the clinical and radiological outcomes of spinal reconstruction after multilevel TES.

METHODS

Forty-eight patients treated with multilevel TES at our institute were included in the analysis. Reconstruction was achieved with posterior pedicle screw fixation and an anterior titanium mesh cage filled with iliac autograft in all cases. Spinal shortening was performed to increase spinal stability from the reconstruction. Instrumentation failure and radiological findings were evaluated with radiography and computerized tomography (CT).

RESULTS

After excluding one patient whose general condition was deteriorating, radiological evaluations of 47 patients were performed over a period of more than a year. The follow-up time was 17 to 120 months (mean: 70.2 months). Instrumentation failure occurred in one patient (5.9%) after thoracic multilevel TES, in 4 patients (25.0%) after thoracolumbar multilevel TES, and in 3 patients (42.9%) after lumbar multilevel TES. No instrumentation failure was observed in cervicothoracic cases. Cage subsidence (>2 mm) occurred in 30 patients (63.8%). In 22 of them, subsidence appeared on the CT one month after surgery. The risk factors of instrumentation failure included a multilevel TES below the thoracolumbar level and a long span of vertebral resection. There was no instrumentation failure in any of the 11 "disc-to-disc cutting" cases.

CONCLUSIONS

This study identified the risk factors of instrumentation failure after multilevel TES. There is a high risk of instrumentation failure in cases of long vertebral resection below the thoracolumbar level. On the other hand, our reconstruction method can be successful for multilevel TES above the thoracic level.

[Total en bloc spondylectomy for spinal tumours: Technical aspects and surgical details]

OBJECTIVE

To describe the specific surgical details and report the lessons learned with a series of patients suffering from spinal tumours that underwent total en bloc spondylectomy (TES).

METHODS

A retrospective case series review is presented, together with an analysis of the clinical and technical variables, as well as the outcomes.

RESULTS

A total of 10 patients underwent TES (2000-2016) for primary (osteosarcoma, chondrosarcoma, fibrosarcoma and chordoma) and secondary spinal tumours (lung, breast, thyroid, oesophagus, and meningioma metastases). According to the Tomita classification, 2 patients had intra-compartmental tumours, and the rest presented as extra-compartmental. All patients experienced an improvement in their pain level after surgery. Nine patients preserved ambulation post-operatively and one patient developed paraplegia. Six patients needed subsequent operations for wound debridement, tumour recurrence, or revision of the fixation. Other complications included pneumothorax, pleural effusion and venous thrombosis. Four patients remain alive (4 months to 15 years follow-up). The rest died due to primary tumour progression (6.5 months to 12 years). A detailed description of the surgical steps, tips, and pitfalls is provided. Modifications of the technique and adjuncts to resection are commented on. Observation of some considerations (selection of candidates, careful blunt vertebral dissection, strict blood loss control, careful handling of the spinal cord, and maintenance of the radical resection concept at all stages) is key for a successful operative performance.

CONCLUSION

TES is a paradigmatic operation, in which the concept of radical resection provides functional effectiveness and improves survival in selected patients suffering from spinal tumours. Our preliminary experience allows us to highlight some specific and relevant features, especially those favouring a simpler and safer operation.

Fixed-Angle, Posteriorly Connected Anterior Cage Reconstruction Improves Stiffness and Decreases Cancellous Subsidence in a Spondylectomy Model

STUDY DESIGN

An idealized biomechanical model.

OBJECTIVE

The aim of this study was to evaluate the biomechanical properties of a construct designed to minimize intervertebral cage subsidence and maximize stiffness.

SUMMARY OF BACKGROUND DATA

Reconstruction after vertebral resection typically involves posterior segmental fixation and anterior interbody support. However, poor bone density, adjuvant radiation, or the oncologic need for endplate resection make interbody device subsidence and resultant instrumentation failure a significant concern.

METHODS

An idealized thoracolumbar spondylectomy reconstruction model was constructed using titanium segmental instrumentation and Delrin plastic. In vivo mechanical stress was simulated on a custom multi-axis spine simulator. Rigid body position in space was measured using an optical motion-capture system. Cancellous subsidence was modeled using a 1 cm thick wafer of number 3 closed-cell Sawbones foam at one endplate. Ten foam specimens were tested in a control state consisting of posterior segmental fixation with a free interbody cage. Ten additional foam specimens were tested in the test state, with the Delrin interbody cage "connected" to the posterior rods using two additional pedicle screws placed into the cage. Foam indentation was quantified using a precision digital surface-mapping device, and subsidence volume calculated using geometric integration.

RESULTS

The control group exhibited significantly greater foam indentation after cycling, with a mean subsidence volume of 1906 mm [95% confidence interval (95% CI) 1810-2001] than the connected cage group subsidence volume of 977 mm (95% CI 928-1026 mm; P < 0.001]. Construct stiffness was greater in the connected cage group (3.1 Nm/degree, 95% CI 3.1-3.2) than in the control group (2.3 Nm/degree, 95% CI 2.2-2.4; P < 0.001).

CONCLUSION

In an idealized spondylectomy model, connecting the anterior column cage to the posterior instrumentation using additional pedicle screws results in a construct that is nearly 40% stiffer and exhibits 50% less cancellous subsidence compared with a traditional unconnected cage.

LEVEL OF EVIDENCE

N/A.

A biomechanical comparison of 360° stabilizations for corpectomy and total spondylectomy: a cadaveric study in the thoracolumbar spine

Background

To date, there has been no adequate biomechanical model that would allow a quantitative comparison in terms of stability/stiffness between a corpectomy with the posterior column preserved and a total spondylectomy with the posterior column sacrificed. The objective of this study was to perform a biomechanical comparison of 360° stabilizations for corpectomy and total spondylectomy, using the human thoracolumbar spine.

Methods

Five human cadaveric thoracolumbar spines (T8-L2) were tested according to the following loading protocol: axial compression, flexion, extension, lateral bending to the right and left, and axial rotation to the right and left. This loading protocol was applied three times. Each specimen was tested intact, after corpectomy, and after total spondylectomy. The relative stiffness of each motion segment was determined for each test.

Results

There was no significant difference in stiffness after reconstruction of total spondylectomy versus corpectomy in our thoracolumbar model. Our construct consisted of an anterior cage and four-level pedicle screw instrumentation (two above and two below) and provided similar stiffness in both models. Despite the additional bone resection in a total spondylectomy versus corpectomy, the constructs did not differ biomechanically. Additionally, there was no significant difference in stiffness between the intact specimen and either reconstruction model.

Conclusions

A classic corpectomy, which leaves the posterior column intact, is no better in terms of stability/stiffness than a total spondylectomy carried out using a shorter cage, followed by compression using posterior instrumentation.

Clinical outcome of spinal reconstruction after total en bloc spondylectomy at 3 or more levels

STUDY DESIGN

Retrospective clinical study.

OBJECTIVE

To assess the clinical and radiological outcome of spinal reconstruction after total en bloc spondylectomy (TES) at 3 or more levels.

SUMMARY OF BACKGROUND DATA

There have been few reports of multilevel spondylectomy for spinal tumor. This is the first case series on the clinical outcome for reconstructions after 3 or more levels of TES.

METHODS

Twenty-six patients treated by 3 or more levels of TES at Kanazawa University Hospital were included in this analysis. Reconstruction was performed with pedicle screw fixation and a titanium mesh cage filled with autograft in all cases. To increase spinal stability in reconstruction, spinal shortening was performed. Instrument failure and radiological findings were evaluated using radiograph and computed tomographical scan with multiplanar reconstructions. The length of spinal shortening was also measured.

RESULTS

Excluding 4 patients with deteriorating general condition, radiological evaluation was performed for more than 1 year in 22 patients. All 22 patients had no evidence of local recurrence at the surgical site of the spine during the follow-up period. Cage subsidence was seen in 11 patients (50%). Eight of the 11 patients showed the appearance of subsidence 1 month after the surgery. There was one instrument failure that required revision surgery 8 months after TES surgery. One other patient showed bone resorption on the contact surfaces of the cage at 24 months after the surgery. The mean length of the resection vertebrae was 84.6 mm (52-124 mm), while the length of the shortening was 10.4 mm (3-22 mm).

CONCLUSION

No local recurrence was observed after TES at 3 or more levels. Cage subsidence was a common phenomenon (50%) and already observed 1 month after surgery in 8 of the 11 cases. Spinal shortening has the potential to provide good stability for multilevel TES.

LEVEL OF EVIDENCE

4.

More than 10-year follow-up after total en bloc spondylectomy for spinal tumors

BACKGROUND

There are many reports of en bloc resection for spinal tumors. However, no studies have evaluated the clinical outcomes with follow-up exceeding 10 years after surgery.

METHODS

We reviewed 82 patients who had undergone total en bloc spondylectomy (TES) before January 2002 and identified 29 (19 with primary tumors and 10 with metastatic tumors) who had survived for more than 10 years after surgery. We evaluated the clinical outcomes including patient-based outcomes using questionnaire. The questionnaire included subjective assessment of the results of TES and SF-36.

RESULTS

Overall, 33 % of patients with metastases from kidney cancer and 25 % of those with metastases from thyroid cancer survived for more than 10 years after TES for solitary spinal metastases. Four patients with metastatic tumors had no evidence of disease at the time of survey. There were no tumor recurrences in any of the 23 patients who underwent TES as the primary surgery. No revision surgeries have been required as a result of instrumentation failure in any of the 29 patients. About 90 % of the patients were satisfied or very satisfied with the results of TES. The SF-36 results demonstrated that the both physical and mental health of patients with primary tumors was equivalent to those of healthy individuals, and the mental health of patients with metastatic tumors was almost similar to them.

CONCLUSIONS

This study showed the long-term clinical outcomes after TES to be favorable. TES played an important role in the treatment strategy for spinal tumors including metastases.