Elsevier

The Spine Journal

Volume 14, Issue 11, 1 November 2014, Pages 2608-2617
The Spine Journal

Clinical Study
En bloc resections for primary spinal tumors in 20 years of experience: effectiveness and safety

https://doi.org/10.1016/j.spinee.2014.02.030Get rights and content

Abstract

Background context

Many studies have demonstrated that en bloc surgical resection of primary spinal tumors with adequate margins results in improved local disease control and survival compared with intralesional excision. Nevertheless, the use of this procedure is under debate because most of the current evidence is provided by small and heterogeneous series of cases.

Purpose

To validate the application of en bloc resection for the treatment of aggressive benign and primary malignant spinal tumors.

Study design

This is a prospective cohort study.

Patient sample

From August 1990 to March 2010, 103 consecutive patients affected by primary spinal tumors were enrolled in the study. All patients were submitted to the same clinical and imaging workup.

Outcome measures

Analysis of local recurrence (LR) and tumor-related mortality, reliability of preoperative surgical planning, and morbidity and mortality. In addition, the effects of possible predictors of these events were studied.

Methods

The parameters for the effectiveness and safety of en bloc resections performed on primary spinal tumors were considered as primary end points of this study, and two research questions were formulated. The analysis of the procedure effectiveness considered the identification of possible predictors of LR and tumor-related mortality. Information about safety is collected so as to clarify the possibility to respect the preoperative planning and to identify possible predictors of morbidity and mortality. Data from clinical and imaging examination were collected in a database and were used to answer the proposed research questions.

Results

All patients were followed for a minimum of 24 months or until death. At the final assessment, 69 patients resulted with no evidence of disease with a mean follow-up of 100 months. Among the 103 patients, tumor recurred in 22 cases with a mean follow-up period of 39 months after surgery. A Cox regression multivariate analysis shows that marginal and intralesional resections are independent predictors of LR (hazard ratio [HR] 9.45, 95% confidence interval [CI] 1.06–84.47 and HR 38.62, 95% CI 4.67–319.21, respectively, compared with wide resection) and tumor-related mortality (in particular, HR 17.10, 95% CI 3.80–77.04 for intralesional resection compared with the wide one). The same analysis demonstrates that en bloc resection performed in recurrent cases or patients previously submitted to open biopsy (nonintact cases) have a LR risk higher than intact cases (HR 3.45, 95% CI 1.38–8.63). The success rate of en bloc resections in achieving adequate margins is 82.4%, and Weinstein-Boriani-Biagini surgical staging can also predict the margins in a high percentage of cases (75.7%). Complications occurred in 41.7% of patients with a higher rate observed in the nonintact group and for surgery with a double-approach or multisegmental resections. The mortality rate related to surgery complications was 1.9%, whereas tumor-related mortality was 15.5%.

Conclusions

Statistical analysis of the long-term results referred to 103 patients affected by aggressive benign and malignant primary spine tumors indicates that an en bloc resection is associated with a high rate of complications. Nevertheless, it decreases the risk of LR and tumor-related mortality. En bloc resection is a highly demanding procedure but can be performed to an acceptable degree of safety.

Introduction

Evidence & Methods

Although a number of studies support the benefits of en-bloc surgical resection for survival in the setting of benign-aggressive and malignant spinal tumors, information is limited regarding long-term outcomes. Furthermore, most data are derived from small retrospective series and case reports. To address this shortcoming, the authors endeavored to present results for a series of 103 consecutive patients treated with en-bloc vertebral resection over a 20-year period.

At mean follow-up of 100 months, 69 patients treated with en-bloc resection showed no evidence of disease recurrence. The success rate of en-bloc resection in achieving adequate margins was determined to be approximately 82%. Postoperative complications occurred in over 40% of patients and post-surgical mortality approached 2%.

This study makes a valuable contribution to the literature in terms of its capacity to provide long-term follow-up data on a large series of patients treated with en-bloc vertebral resection. Given the rarity of these tumors, as well as the ethical implications associated with treatment, it is difficult to envision that research providing a higher level of evidence is possible. Nonetheless, in spite of the methods used by the authors to collect their data, this series is uncontrolled and subject to substantial confounding by indication. While clearly demonstrating the complication-profile and potential benefit the en-bloc technique has for select individuals, the evidence presented cannot be considered anything above level IV. In addition, as the authors themselves emphasize, the results achieved by a surgical center with vast experience in treating these types of complex spinal tumors are not necessarily translatable to other hospitals or health care systems.

—The Editors

Primary bone tumors of the spine are extremely rare. They represent 11% [1] of all primary tumors of the musculoskeletal system, 4.2% [2] of all spinal tumors, and approximately 0.4% [3] of all malignancies.

En bloc resection of primary tumors refers to the surgical removal of the whole tumor in a single piece, fully encased by a layer of healthy tissue. This procedure was first proposed by Enneking et al. [4] for bone and soft-tissue limb tumors, possibly in combination with adjuvant chemotherapy within the so-called “limb salvage surgery.” The new procedure dramatically reduced the rate of amputations without the negative impact and sometimes even improving the local and systemic disease control.

The application of this philosophy to spinal bone tumors is debatable because of anatomic constraints and to the proximity of unresectable structures. Stener [5] was the first pioneer of en bloc resections in the spine, followed later on by Roy-Camille et al. [6], and finally by Tomita et al. [7]. According to histologic diagnosis and oncological staging system [4], en bloc resection in the spine is indicated for aggressive benign tumors (Stage 3) and malignant primary tumors. Adjuvant treatments should also be considered for high-grade malignancies. The Weinstein-Boriani-Biagini (WBB) surgical staging system [8] was created for planning en bloc resection to achieve the appropriate histologic margins, and it has been validated both clinically [9] and by a reliability assessment [10].

En bloc resection, however, is mostly a very demanding surgery, associated with high morbidity. Functionally relevant structures are often contiguous with the tumor or invaded by it. The sacrifice of these structures, such as nerve roots, is sometimes required to achieve an appropriate margin.

Discussion is open regarding balancing surgical aggressiveness planned on Enneking criteria, possibly provoking severe functional damages versus intentional transgression to these principles to save function [9], combined with adjuvant therapies.

The decision-making process, therefore, should include not only oncological criteria but also a risk/benefit discussion considering the sacrifices required to achieve the appropriate margins.

The results obtained from the previous publication support the use of en bloc resection in the surgical management of primary tumors of the spine, despite the low quality of evidence of the literature because of the rarity of these tumors [9], [11], [12], [13], [14], [15], [16], [17], [18]. In addition, the use of different terminology reduces the level of reliability [11], [19], [20], [21].

The authors collected the data from 103 consecutive patients submitted to en bloc resection during 20 years of experience in a single institution. Data were analyzed according to a careful methodology [22] in a prospective cohort study to validate the application of en bloc resection to the aggressive benign and primary malignant spinal tumors.

To assess the effectiveness and the safety of this procedure, we formulated two research questions. First, we sought to examine whether surgical margins obtained during en bloc resection (among other surgical and clinical parameters) predicted recurrence or mortality. As secondary goals, we sought to describe the effect of the diagnostic workup on the results and the morbidity and mortality of these procedures.

Section snippets

Data collection

The inclusion criteria of this prospective cohort study were en bloc resection performed between August 1990 and March 2010 for a primary spinal tumor and follow-up for a minimum of 24 months or until death.

Collection of demographic and operative data included gender, age, previous treatment, type of biopsy, tumor type, physical and neurologic status, pathologic fracture, anatomic location, spinal level(s), Enneking oncological staging system, WBB surgical staging system, surgical approach,

Demographic, operative, and follow-up details

From August 1990 to March 2010, 1,180 bone tumors of the spine (544 of those primaries) were treated by the same team. One hundred and three patients were eligible for this study. The series included 51 women and 52 men. The mean age at the time of surgery was 42 (median 40, range 3–83) years.

Twenty-six patients were defined as “nonintact cases”: 24 referred from another institution either with tumor recurrence after an intralesional excision or with contamination of the epidural space after an

Discussion

Application to the spine of the concept of en bloc tumor resection was started by Stener [5] with his brilliant and detailed report of a single case. Later on, Roy-Camille et al. [6] and followed by Tomita et al. [7] systemized the procedure by single posterior approach.

Indication to oncological resection requires a system to standardize the criteria to make a primary tumor eligible for en bloc resection: benign aggressive, low-grade malignancies, and high grade only if combined with chemo and

Conclusions

Our results support the treatment of spinal aggressive benign and malignant bone tumors through en bloc resections, in terms of better local control and prognosis, although it is a highly demanding and risky procedure. Margins are the key point of this surgical procedure. Wide or marginal margins are necessary to improve outcomes in term of lower risk of LR and tumor-related mortality. Moreover, a careful preoperative oncological and surgical staging is necessary to define the optimal surgical

Acknowledgments

The Authors thank Tiziana De Santo for her most valuable assistance in statistical analysis, and Carlo Piovani for imaging assistance.

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      En bloc resections, first proposed by Enneking et al., are aimed at the surgical removal of a tumor in a single, intact piece, fully encased by healthy tissue.2 En bloc resections are currently the most effective surgical management strategy for tumors involving spine,1,3-10 but still represent relatively morbid procedures due to complex surgical approaches, large exposures, and the potential involvement of the tumor into functionally and anatomically important structures.7,11-13 While conventional computed tomography (CT)-guided navigation has shown improvements in accuracy and reductions in complications,14-16 surgeons are limited by the need for a shift in attention to a heads-up display.17

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    Author disclosures: LA: Nothing to disclose. MC: Nothing to disclose. FDI: Nothing to disclose. SBa: Nothing to disclose. AG: Nothing to disclose. SBo: Nothing to disclose.

    The authors declare that they have no conflict of interest related to the publication of the article, and no funds were received in support of this work. No benefits in any form have been or will be received from a commercial party related directly or indirectly to the subject of the article.

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