En bloc resection of primary tumors of the thoracic spine: indications, planning, morbidity

Single-Stage Combined Approach Sagittal En Bloc Spondylectomy for L3 Vertebral Chondrosarcoma: A Technical Note

BACKGROUND

Primary malignant tumors of the spine are rare and most commonly occur in lumbar and thoracic vertebrae. We report a rare case of retroperitoneal chondrosarcoma of L3 that was managed with sagittal en bloc spondylectomy following chemoradiation.

CASE DESCRIPTION

A 26-year-old woman was evaluated for abdominal pain with contrast-enhanced computed tomography of the abdomen and pelvis, which revealed a soft tissue retroperitoneal mass arising from L3. She underwent laparotomy and biopsy, which revealed chondrosarcoma, and she received chemoradiation over a period of 28 weeks 6 days. After repeat imaging, she underwent single-stage combined approach sagittal en bloc spondylectomy of retroperitoneal chondrosarcoma of L3 with right nephrectomy and spine reconstruction. At 3-year follow-up, there was no evidence of recurrence on contrast-enhanced computed tomography of the abdomen and pelvis. She demonstrated no gait abnormality or spinal deformity.

CONCLUSIONS

Sagittal en bloc spondylectomy is a preferred surgical approach for eccentrically placed spinal tumors that offers better oncological and functional outcomes.

Sagittal en bloc resection of thoracolumbar tumours: a report of thirty one cases

PURPOSE

To develop a novel classification of sagittal en bloc resection (SEBR) based on anatomical locations for thoracolumbar spine tumors and assess the clinical outcomes of this surgical procedure.

METHODS

31 patients with thoracolumbar tumours treated with SEBR were enrolled in this study. The individualized surgical strategy was adopted based on our surgical classification. Demographics, perioperative outcomes, complications and postoperative outcomes were assessed.

RESULTS

Based on our surgical classifications, patients were divided into four types. All bony resection margins were negative, wide resection was achieved in 25 patients, marginal resection in four, and intralesional resection in two. 18 patients underwent anterior reconstruction. Complications were encountered in five patients, and instrumentation failure occurred in one patient. The median follow-up was 24 (range, 6-72) months and recurrence was found in only one patient.

CONCLUSION

SEBR is a safe and effective surgical procedure for patients with thoracolumbar spinal tumours in specific anatomical locations. The proposed surgical classification covers all SEBR types and is easy to apply, it may assist surgical decision-making in patients with spinal tumours.

Surgical outcomes and risk factors for surgical complications after en bloc resection following reconstruction with 3D-printed artificial vertebral body for thoracolumbar tumors

BACKGROUND

The outcomes of patients with tumors of the thoracolumbar spine treated with en bloc resection (EBR) using three-dimensional (3D)-printed endoprostheses are underreported.

METHODS

We retrospectively evaluated patients with thoracolumbar tumors who underwent surgery at our institution. Logistic regression analysis was performed to identify the potential risk factors for surgical complications. Nomograms to predict complications were constructed and validated.

RESULTS

A total of 53 patients with spinal tumors underwent EBR at our hospital; of these, 2 were lost to follow-up, 45 underwent total en bloc spondylectomy, and 6 were treated with sagittal en bloc spondylectomy. The anterior reconstruction materials included a customized 3D-printed artificial vertebral body (AVB) in 10 cases and an off-the-shelf 3D-printed AVB in 41 cases, and prosthesis mismatch occurred in 2 patients reconstructed with the off-the-shelf 3D-printed AVB. The median follow-up period was 21 months (range, 7-57 months). Three patients experienced local recurrence, and 5 patients died at the final follow-up. A total of 50 perioperative complications were encountered in 29 patients, including 25 major and 25 minor complications. Instrumentation failure occurred in 1 patient, and no prosthesis subsidence was observed. Using a combined surgical approach was a dependent predictor of overall complications, while Karnofsky performance status score, lumbar spine lesion, and intraoperative blood loss ≥ 2000 mL were predictors of major complications. Nomograms for the overall and major complications were constructed using these factors, with C-indices of 0.850 and 0.891, respectively.

CONCLUSIONS

EBR is essential for the management of thoracolumbar tumors; however, EBR has a steep learning curve and a high complication rate. A 3D-printed AVB is an effective and feasible reconstruction option for patients treated with EBR.

Chondrosarcoma secondary to hereditary multiple osteochondromas with spinal cord compression: A case report and systematic review

Background

Hereditary multiple osteochondromas (HMOs) are a rare genetic disorder characterized by the formation of multiple benign osteochondromas that can undergo malignant transformation into chondrosarcoma.

Case Description

A 24-year-old male with a history of HMO and osteochondroma surgery 4 years ago, presented with back pain and paresthesias. The magnetic resonance showed a right paravertebral infiltrating mass at the T12-L1 level causing spinal cord compression. Following en bloc resection of the tumor, the patient's symptoms/ signs resolved. The final pathological diagnosis was consistent with a chondrosarcoma.

Conclusion

Chondrosarcomas secondary to HMO with spinal cord compression are rare. These patients often presenting with significant myelopathy/cord compression should undergo gross total resection where feasible to achieve the best outcomes.

Management of symptomatic spine metastases: A multidisciplinary approach based flow-chart

We described an algorithm for the management of spinal metastases in which the importance of single parameters varies depending on when they are contemplated. Each patient follows his own «personal» sequential process which does not necessarily consider all the parameters each time as some may be irrelevant for the purpose of choosing the type of treatment for that single individual. For instance, a patient in general poor condition with a high ASA score is usually not a candidate for surgery, regardless of the primary tumor nature or the number of metastases. For this patient, the most important element would be the sensitivity of the tumor to adjuvant treatment. Similarly, a patient with acute and progressive spinal cord injury would undergo surgical decompression and stabilization without considering a more strenuous intervention.

Management of symptomatic spine metastases: A multidisciplinary approach based flow-chart

We described an algorithm for the management of spinal metastases in which the importance of single parameters varies depending on when they are contemplated. Each patient follows his own "personal" sequential process which does not necessarily consider all the parameters each time as some may be irrelevant for the purpose of choosing the type of treatment for that single individual. For instance, a patient in general poor condition with a high "ASA" score is usually not a candidate for surgery, regardless of the primary tumor nature or the number of metastases. For this patient, the most important element would be the sensitivity of the tumor to adjuvant treatment. Similarly, a patient with acute and progressive spinal cord injury would undergo surgical decompression and stabilization without considering a more strenuous intervention.

Complications and Risk Factors in En Bloc Resection of Spinal Tumors: A Retrospective Analysis on 298 Patients Treated in a Single Institution

En bloc resection consists in the surgical removal of a vertebral tumor in a single piece with a sufficient margin, to improve survival and reduce recurrence rate. This procedure is technically demanding and correlates with a high complication rate. The purpose of this study is to investigate the risk factors for complications in en bloc resection and evaluate if benefits overcome the risks in term of overall survival. We retrospectively analyzed prospectively collected data of patients treated with en bloc resection between 1980 and 2021. Complications were classified according to SAVES-V2. Overall Survival was estimated using Kaplan-Meier method. A total of 149 patients out of 298 (50%) suffered from at least one complication. Moreover, 220 adverse events were collected (67 intraoperative, 82 early post-operative, 71 late post-operative), 54% of these were classified as grade 3 (in a severity scale from 1 to 6). Ten years overall survival was 67% (95% CI 59-74). The occurrence of relapses was associated to an increased risk of mortality with OR 3.4 (95% CI 2.1-5.5), while complications did not affect the overall survival. Despite a high complication rate, en bloc resection allows for a better control of disease and should be performed in selected patients by specialized surgeons.

Treatment of spinal deformity with diastematomyelia type I: one-stage, two-stage surgery and new technique (vertebral column resection through wide bony septum)

STUDY DESIGN

Case series, literature review, and technical note.

OBJECTIVES

To compare two different approaches to treat the spinal deformity with split cord malformation type I (SCM I). To present a new method of one-stage surgical treatment of congenital spinal deformity with wide bony septum (SCM I).

METHODS

Analysis of the literature on the different types of combined surgical treatment of spinal deformities with SCM I was performed. We have provided our own data on 27 patients treated for congenital spinal deformity and SCM I, one of which underwent Schwab IV type osteotomy at the apex of the deformity through the bony septum and pedicles. Inclusion criteria were presence of spinal deformity in combination with SCM 1, performed surgery to correct spinal deformity, and follow-up period of at least 2 years.

RESULTS

The result of the literature review was controversial and requires additional research. The average age of patients was 8.8 ± 6.6 years old. One-stage treatment of SCM I and spinal deformity was performed in 10 patients (group I) and two-stage in 14 patients (group II). Three patients with severe myelodysplasia, SCM I, and congenital kyphoscoliosis underwent correction of spinal deformity without SCM I removing (group III). The group I had the longest surgery duration (mean 289 ± 75 min) and largest blood loss (mean 560 ± 386 ml), a high percentage of deformity correction (mean 69.6%), and the highest rate of complications (60%). The most optimal was the two-stage treatment with the mean surgery duration 191 ± 137 min, mean blood loss 339 ± 436 ml, mean correction rate 63%, and frequency of complications 21%. The average follow-up time was 6.0 ± 2.6 years.

CONCLUSIONS

One stage surgery associated with a large surgical invasion and a large number of complications. It can be used in some cases, for example when the wide bony septum (SCM I) is localized at the apex of the congenital scoliosis or kyphosis. In all other cases, it is worth adhering to a two-stage treatment. Many new works demonstrate the relative safety and effectiveness of deformity correction without removing the SCM. In our opinion, indications for treatment of spinal deformity without SCM I removing can be the need to perform a shortening ostetomy outside the SCM zone. The remaining cases require a thorough assessment and a balanced decision.

En bloc resection and reconstruction of a huge chondrosarcoma involving multilevel upper thoracic spine and chest wall: case report

Background

En bloc resection of malignant tumors involving upper thoracic spine is technically difficult. We surgically treated a patient with grade 2 chondrosarcoma involving T1–5, left upper thoracic cavity, and chest wall.

Case presentation

A 37 years old, male patient was referred to our hospital for a huge lump involved left shoulder and chest wall. In order to achieve satisfied surgical margins, anterior approach, posterior approach, and lateral approach were carried out sequentially. After en bloc tumor resection, the upper thoracic spine was reconstructed with a 3D-printed modular vertebral prosthesis, and the huge chest wall defect was repaired by a methyl methacrylate layer between 2 pieces of polypropylene mesh. Postoperatively, the patient suffered from pneumonia and neurological deterioration which fully recovered eventfully. At 24 months after operation, the vertebral prosthesis and internal fixation were intact; there was no tumor local recurrence, and the patient was alive with stable pulmonary metastases.

Conclusion

This case report describes resection of a huge chondrosarcoma involving not only multilevel upper thoracic spine, but also entire left upper thoracic cavity and chest wall. Although with complications, en bloc tumor resection with combined surgical approach and effective reconstructions could improve oncologic and functional prognosis in carefully selected spinal tumor patients.

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.

Median Sacral Artery Rupture as a Complication of Posterior-Only Approach of L4 Total En Bloc Spondilectomy: A Case Report

CASE

A 6-year-old patient with Ewing sarcoma at L4 who was treated with total en bloc spondilectomy (TES) through a posterior-only approach. During the dissection of the anterior L4 body, there was uncontrollable bleeding from an unknown origin, which needed packing, massive transfusion, and urgent laparotomy. A median sacral artery (MSA) rupture was identified as the cause of this massive bleeding. Eventually, the patient was successfully stabilized.

CONCLUSIONS

To our knowledge, this is the first reported intraoperative bleeding of the MSA related to a lumbar TES through posterior-only approach. This life-threatening complication should be considered when planning for this type of surgery.

Sagittal en bloc resection of primary tumors in the thoracic and lumbar spine: feasibility, safety and outcome

This study is to test feasibility, safety and the outcome of sagittal en bloc resection of paravertebral primary tumors in the thoracic and the lumbar spine. Sagittal en bloc resection was planned based on WBB classification and performed via combined anterior-posterior or anterior-posterior-lateral approach in 9 consecutive patients with aggressive benign or malignant paravertebral primary tumors in the thoracic and lumbar spine. Surgical margins were evaluated both radiologically and histopathologically. Follow-up data regarding survival rate, local control, morbidity, hardware failure and postoperative function were collected at around 2 years after surgery. En bloc resection was achieved in all patient with wide margin in 7/9 patients, marginal and intralesional margin in 2/9 patients. Survival rate and local control rate were 100%. There were 4/9 cases of major complications and 2/9 cases of minor complications with an overall morbidity rate of 67% (6/9). All but one patient with intraoperative spinal cord injury were free of neurological deficits and fully mobile in absence of any indication of hardware failure. With a careful choice of surgical procedure, sagittal en bloc resection of paravertebral primary tumor in the thoracic and lumbar spine is feasible, safe and effective.

Denosumab in the treatment of giant cell tumor of the spine. Preliminary report, review of the literature and protocol proposal

BACKGROUND

The interest on the role of Denosumab in the treatment strategy of giant cell tumor of the spine is growing. En bloc resection is considered the Enneking appropriate treatment, but morbidity and functional loss are sometimes unacceptable. Denosumab could play a role as a stand-alone treatment, but also as preoperative treatment or as postoperative after intralesional surgery.

MATERIALS AND METHODS

A cohort of 10 out of 12 cases of spinal GCT consecutively treated with Denosumab are analyzed and discussed compared to the cases reported in the literature. A staging of the radiological effect of the treatment is proposed.

RESULTS

The stand-alone and postoperative treatments are still running (12 to 88 months). One therapy was stopped after 15 months, once a satisfactory local effect was achieved, but the treatment had to be restarted 2 months later due to the recurrence of the erosive images. The new treatment was successful. At 1-year follow-up after the gross total excision followed by postoperative Denosumab treatment, no evidence of local recurrence was found. The preoperative treatment duration ranged from 3 to 24 months. No local recurrence followed the en bloc resections.

CONCLUSIONS

Denosumab alone is effective in relieving pain, increasing the ossification and sometimes reducing the tumor volume. It can be considered an excellent solution in spine GCTs whose surgical treatment cannot be Enneking appropriate or is associated with unacceptable morbidity or loss of functions. It is still impossible to state when to safely stop the treatment. Denosumab also plays a role as preoperative protocol. These slides can be retrieved under Electronic Supplementary Material.

Novel therapeutic strategies for spinal osteosarcomas

At the dawn of the third millennium, cancer has become the bane of twenty-first century man, and remains a predominant public health burden, affecting welfare and life expectancy globally. Spinal osteogenic sarcoma, a primary spinal malignant tumor, is a rare and challenging neoplastic disease to treat. After the conventional therapeutic modalities of chemotherapy, radiation and surgery have been exhausted, there is currently no available alternative therapy in managing cases of spinal osteosarcoma. The defining signatures of tumor survival are characterised by cancer cell ability to stonewall immunogenic attrition and apoptosis by various means. Some of these biomarkers, namely immune-checkpoints, have recently been exploited as druggable targets in osteosarcoma and many other different cancers. These promising strides made by the use of reinvigorated immunotherapeutic approaches may lead to significant reduction in spinal osteosarcoma disease burden and corresponding reciprocity in increase of survival rates. In this review, we provide the background to spinal osteosarcoma, and proceed to elaborate on contribution of the complex ecology within tumor microenvironment giving arise to cancerous immune escape, which is currently receiving considerable attention. We follow this section on the tumor microenvironment by a brief history of cancer immunity. Also, we draw on the current knowledge of treatment gained from incidences of osteosarcoma at other locations of the skeleton (long bones of the extremities in close proximity to the metaphyseal growth plates) to make a case for application of immunity-based tools, such as immune-checkpoint inhibitors and vaccines, and draw attention to adverse upshots of immune-checkpoint blockers as well. Finally, we describe the novel biotechnique of CRISPR/Cas9 that will assist in treatment approaches for personalized medication.

Total en bloc resection of primary and metastatic spine tumors

Primary and metastatic tumors of the spine represent a significant cause of patient morbidity, and present a management challenge to treating providers. From a neurosurgical standpoint, resection surgery may be warranted in cases of spinal instability, progressive disease, neurological compromise, or intractable symptoms. Removal of a tumor "en bloc" offers a more aggressive modality over more conservative resection techniques. En bloc resection entails the removal of the entirety of a tumor without violation of its capsule, and may offer improved rates of local control and overall survival in appropriately selected patients. Conversely, this technique carries a higher complication rate, and requires a unique set of technical skills as compared to more traditional resection. Here, we describe the technical aspects of en bloc resection, as well as specific indications and considerations when employing this operative technique.

Prognostic Factors for Patients With Undifferentiated High Grade Pleomorphic Sarcoma of the Spine

STUDY DESIGN

Retrospective survival analysis of 44 undifferentiated high grade pleomorphic sarcoma (UPS) of the spine.

OBJECTIVE

To identify factors related to overall survival (OS) and help decision making in the treatment of undifferentiated high grade pleomorphic sarcoma of the spine.

SUMMARY OF BACKGROUND DATA

UPS is an aggressive malignant tumor rarely originating from the spine. Due to its scarcity, only a few studies had been reported to describe the clinical features, treatments, and outcomes of sporadic cases, devoid of evaluation on prognostic factors.

METHODS

Enrolled in this survival analysis were 44 patients who underwent surgery and adjuvant therapies from January 1999 to December 2015. Kaplan-Meier methods were applied to estimate the overall survival. A multivariate Cox algorithm was applied to recognize factors independently associated with overall survival.

RESULTS

Multivariate analysis suggested that age greater than or equal to 55 years (hazard ratio [HR], 3.923, P < 0.001), Eastern Cooperative Oncology Group (ECOG) score four (HR, 4.656, P < 0.001), and subtotal resection or piecemeal total resection (HR, 4.375, P < 0.001) were independently associated with poor overall survival.

CONCLUSION

We identified independent prognostic factors of UPS of the spine. Subtotal resection or piecemeal total resection, age more than or equal to 55 years and ECOG score four are factors adversely affecting overall survival of patients with UPS of the spine.

LEVEL OF EVIDENCE

4.

Malignant Transformation and Spine Metastasis of an Intracranial Grade I Meningioma: In Situ Immunofluorescence Analysis of Cancer Stem Cells Case Report and Literature Review

BACKGROUND

Malignant meningiomas are rare neoplasms of the central nervous system that occur de novo or rarely as a result of transformation. They have a higher rate of recurrence and metastasis accompanied by a significantly shorter survivorship compared with benign variants. Meningioma cancer stem cells (CSCs) have been previously shown to be associated with resistance and aggressiveness. However, the role they play in meningioma progression is still being investigated.

CASE DESCRIPTION

We report a 29-year-old man who underwent a resection of a grade I meningioma in 2011. The patient had multiple local recurrences of the tumor that showed an aggressive change in behavior and transformation to grade III meningioma, and developed extracranial metastasis to the cervical spine. He underwent multiple operations and received radiotherapy. Analysis of the tissues indicated the presence of CSC markers before metastasis, and showed increased expressions of associated markers in the metastasized tissue. In addition, similar to the patient's profile, the pharmacological testing of a primary cell line retrieved from the metastasized tissues showed a high level of drug tolerance and a diminished ability to initiate apoptosis.

CONCLUSIONS

Malignant progression of grade I meningioma can occur, and its eventuality may be anticipated by detecting CSCs. We performed a comprehensive literature review of relevant cases and discussed the clinical, diagnostic, and management characteristics of the reported cases.

Huge myxoid chondrosarcoma expanded into the thoracic cavity with spinal involvement

PURPOSE

En bloc resection is the treatment of choice of myxoid chondrosarcoma. These tumors can produce huge masses. Anatomical constraints limit the possibility to perform en bloc resection in the spine.

METHODS

A very huge myxoid chondrosarcoma (14.2 × 10.8 × 11.4 cm) arising from T2 to T5 and invading the whole higher left pleural cavity was observed. Surgical planning according to WBB staging system was performed.

RESULTS

The tumor was successfully submitted to en bloc resection achieving a tumor-free margin as demonstrated by the pathologist's report.

CONCLUSIONS

A careful planning and a multidisciplinary collaboration make possible to perform en bloc resection even in apparently impossible cases.

Radiofrequency ablation in gross total excision of cervical chordoma: ideas and technique

PURPOSE

To use radiofrequency ablation (RFA) in the resection of C4 cervical chordoma with a giant paravertebral tumor mass to achieve tumor-free exposed margins and perform a gross total excision.

METHODS

A gross total excision using combined posterior and anterior approaches was performed. In the posterior stage, the C4 posterior arch was removed and the C4/C5 nerve roots and vertebral artery were released from the tumor. In the anterior stage, the giant soft mass of tumor from C3 to C6 was treated with RFA to make it shrink and solidify visually to achieve tumor-free exposed margins before resecting the tumor. Finally, a gross total excision was performed followed by the implantation of titanium plate and mesh filled with allograft bone.

RESULTS

A gross total excision was performed with tumor-free exposed margins and radiotherapy. The patient survived more than 5 years without recurrence.

CONCLUSIONS

RFA can help achieve tumor-free exposed margins. A gross total excision combined with RFA can improve the local relapse-free survival of patients with cervical chordoma. These slides can be retrieved under Electronic Supplementary Material.

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.