Total vertebrectomy through posterior approach for thoracic tumors

Objective: To demonstrate the benefi ts and complications of the single posterior approach through bilateral costotransversectomy in the treatment of neoplastic disease of the thoracic spine. Methods: Twelve consecutive patients with thoracic spine tumors, who underwent single posterior approach with bilateral costotransversectomies were reviewed. Through posterior extrapleural access, total vertebrectomy and reconstruction were performed. In reconstruction, a cage was used anteriorly, and a pedicular screw fi xation was used posteriorly. The minimum follow-up was sixteen months. The parameters analyzed were pain, neurological and functional capacity, survival time, fi xation stability, and complications. Results: All patients had improvement in their pain or in their functional capability. Among those with a preoperative neurological defi cit, 71.4% showed improvement of at least one degree at postoperative evaluation. There was no functional or neurological decline in any patient. The observed complications were: one adult respiratory stress syndrome, one excessive bleeding, one pneumothorax, one infection and one local recurrence. All but one of these complications was reversed with appropriate treatment. Conclusion: The posterolateral approach through costotransversectomy was safe and secure method for the resection and reconstruction of thoracic vertebrae affected by neoplastic disease. Research Article Total vertebrectomy through posterior approach for thoracic tumors Jefferson Soares Leal*, Rogério Lúcio Chaves de Resende, Daniel Ferreira Ghedini, Leandro Vinícius Vital, Haroldo Oliveira de Freitas Júnior and Luiz Eduardo Moreira Teixeira Department of Orthopedic, Spine Surgery Unit, Federal University of Minas Gerais / Biocor Institute, Belo Horizonte, Brazil Received: 07 April, 2021 Accepted: 15 May, 2021 Published: 17 May, 2021 *Corresponding author: Jefferson Soares Leal, Department of Orthopedic, Spine Surgery Unit, Federal University of Minas Gerais / Biocor Institute, Rua Padre Rolim, 815, Vertebra Clinic, Santa Efi gênia, Belo Horizonte, MG 30130-090, Brazil, Tel: +5531992063634; Fax: +553132227587; E-mail:


Introduction
The best surgical treatment for localized malignant bone tumors is the wide surgical margins resection. Nevertheless, the resection of malignant tumors of the spine is incomparably more diffi cult than those in limbs. The topographic proximity of vital structures to the vertebral column, such as the spinal cord, nerve roots, aorta artery and vena cava, limits the feasibility and complicates the performance of wide resection margins for malignant vertebral tumors. Additionally, extracompartmental tumor growth with dural extension or anterior invasion around greater vascular structures does not allow for wide resection. Thus, in many instances, a technique that provides good decompression and stability with less morbidity can be the best for certain patients. In our series, all patients were not eligible for a total en bloc spondylectomy.
It is generally accepted that when the compressive lesion is anterior, the surgical approach should be anterior, followed by decompression and stabilization. In the thoracic spine, this usually requires thoracotomy or thoracoscopy [1]. However, in the upper thoracic spine the anterior approach can be diffi cult to perform because of the kyphosis and the proximity of the heart, lungs, and greater vessels [2]. These special features are important barriers for resection and stable reconstruction of the vertebral body through cervicosternotomy or transcavitary approaches.
Costotransversectomy was fi rst described for abscess Citation: Leal  In this technique, a medial segment of the rib is removed in a manner which allows extrapleural access to the vertebral body, without the necessity of opening the thoracic cavity. Anterior extrapleural approach through costotransversectomy for vertebral body tumor extirpation allows circumferential decompression of the spinal cord and has been described by several authors [3]. However, in most of these studies, the results were not very encouraging, mainly due to the lack of a reliable reconstruction technique following resection [4]. More recently, with the dissemination of more stable spine fi xation systems [5], this approach has been more commonly used, and has again aroused interest in the treatment of thoracic spine tumors, especially when the en bloc resection is not feasible, as it may be considered less risky [6].
The extrapleural costotransversectomy approach offers the potential advantage of avoiding tumor dissemination to the pleural space and worsening of a pre-existing pulmonary condition that may occur with a transcavitary approach.
Lesions which infi ltrate the vertebral arch posteriorly may also be resected through the same single approach.

Surgical technique
With the spine exposed posteriorly, pedicle screws were inserted segmentally in two segments above and two below the Following this step, another rod was inserted into this side and securely locked to the screws with slight distraction.
The temporary rod on the opposite side was then removed to allow resection of the remaining vertebra, repeating the same sequences described previously. It should be emphasized that when changing the rod side, one should fi rst connect the second rod on the working side before removing the temporary one. This precaution keeps the spine stabilized during the whole resection procedure, avoiding acute bending of the spinal cord after removing the temporary rod ( Figure 3). At completion of the resection, the spinal cord was checked for a circumferential decompression.
The reconstruction stage began with the insertion of the titanium cage ( Figure 4). The reconstruction procedure fi nished with reinsertion of the second rod, and using the posterior pedicle fi xation system to apply a light compression on the cage bilaterally. The integrity of the pleura was verifi ed, and then the fascia, subcutaneous and skin layers were sutured separately. After 24 hours postoperative, the patient was encouraged to sit after drain removal and a radiological control exam was taken ( Figure 5). After 48 hours, the patient was encouraged to walk, if his or her condition permitted ( Figure 6).

Patient population
In this study, there were six women and six men. The average age was 58.2 years (range, 40-69). All patients presented extra-compartmental infi ltrative lesions involving one pedicle and at least 50% of the vertebral body, and nontraumatic vertebral instability characterized by spontaneous pathological fracture of the vertebral body and progressive worsening of pain. All presented only one level of vertebral involvement in the thoracic region, varying from T2 to T12. Five patients presented no neurological defi cit (Frankel E), fi ve presented incomplete defi cit (Frankel B or C) and two presented complete defi cit (Frankel A). Functionally, according to Akeyson and McCutcheon [3], fi ve patients ambulated without assistance (class I) and seven were confi ned to bed or wheelchair (class III or IV). Five patients (41.6%) underwent preoperative embolization of tumor. Only one patient, who was misdiagnosed as having plasmacytoma, had received preoperative radiotherapy at tenth month before the surgical treatment (Table 1).

Postoperative results
The fi nal anatomopathological diagnoses were four myeloma, three lung adenocarcinomas, two renal cell carcinomas, one plasmacytoma and one prostate carcinoma.
In one patient, the diagnosis was inconclusive postoperatively ( Table 2). The average of the duration of surgery was 412.5 minutes (range, 320-500) with a CI 95% (confi dence interval to 95%) = 374.7 -450.2. Stratifi ed between the fi rst and second halves of the study group series, the surgery time was 458.3 minutes for the fi rst half, and 366.6 minutes for the second   After surgery, the majority of patients experienced an important relief of their pain and improved neurological status. The preoperative average for pain was 6.2 (CI 95% = 4.79 -7.60) while the postoperative average was 2.6 (CI 95% = 1.74 -3.45) (p=0.026). Ten patients experienced improvement of pain postoperatively; one remained unchanged and one died at second month after the surgery before of the fi rst evaluation. One patient (case 1) developed dorsal thoracic pain 16 months after surgery that led to the discovery of a recurrent tumor. According to Frankel classifi cation, fi ve patients improved at least one functional grade and seven remained unchanged postoperatively.
The functional status of all patients was improved or unchanged. Four patients who were confi ned to bed or chair prior to surgery were able to ambulate postoperatively. No patients experienced a decline in their functional or neurological grade as a result of the surgery.
Intraoperative complications were one excessive bleeding in small vessels peripheral to the tumor, and one inadvertent pneumothorax. Postoperative complications were one adult respiratory distress syndrome, one infection with consequent dehiscence of surgical wound, and one local recurrence. No patient presented failure of the anterior or posterior instrumentation, despite that in one case, osteolysis had been seen around the two screws at the distal extremities without compromise to general alignment or the anterior reconstruction (case 1).
In the long term, there were no patients lost at follow-up. At the most recent evaluation, three (25.0%) patients were alive with an average 30 months (range, 16-38) of followup. All of those who were alive continued to maintain their ability to ambulate and normal bowel and bladder function. For the nine patients who died, the average life span after surgical decompression and stabilization was 14.2 months (range, 2-37). There was no death reported during 30 days postoperative.

Discussion
The technique presented in this study describes a simultaneous 360-degree tumor resection and immediate spinal column reconstruction through a single midline approach involving bilateral costotransversectomy in all patients of this series. The main advantages of this technique include: (1) avoidance of thoracotomy, resulting in less risk of damage to the thoracic contents and worsening of pulmonary dysfunction, (2) wide fi eld for resection and reconstruction of the anterior column, and (3) ability to address pedicles or posterior elements infi ltrated without a second approach.
If the anterior approach is chosen for an anterior lesion with neoplastic infi ltration into the pedicle or posterior elements, a second posterior approach is often necessary [8,9]. Moreover, if there is a tumor invasion superior to 50% of the vertebral  Wang, et al. [13] have suggested that the posterolateral approach is limited in not providing direct vision for decompression of the anterior dura. However, other studies have shown that this approach allows complete access to anterior dura [14,15]. Xu, et al. [16] compared the results of vertebrectomy performed using the anterior, posterior and combined approach. In their experience, the three approaches had good functional clinical results, but the posterior approach had the worst performance in terms of infection and deep vein thrombosis. The authors considered the anterior approach to be advantageous over the posterior or combined approach. However, the groups compared were different in relation to some important characteristics. In the group submitted to the posterior approach, the patients were older, the number of patients was twice as high, the number of instrumented levels was signifi cantly higher, and some patients underwent posterior en bloc spondylectomy via Tomita [17], which is a highly complex surgery. Therefore, the results of this study may be distorted due to a possible bias related to the heterogeneity of the groups.
Minimally invasive techniques using the anterior approach are an inexorable trend [1]. However, the learning curve is long  T4  T5  T10  T11  T10  T9  T2  T3  T10  T2  T12  T3   Renal  Prostate  Myeloma  Myeloma  Lung  Renal  Lung  Lung  Plasmacytoma Myeloma Myeloma Plasmacytoma I  I  IV  IV  IV  I  IV  I  III  IV  I I  I  IV  II  IV  I  III  I  I  II  I  II   T2-T6  T3-T7  T8-T12  T9-L1  T8-T12  T7-T11  C7-T4  T1-T5  T8-T12  C7-T4  T10- Local recurrence was diagnosed in case 1 at the 16 th month of follow-up. This patient reported an increase in pain in the thoracic region, and during the course of investigation of this symptom was found out a local recurrence without neurological compression. The recurrence was not treated due to the worsened condition of the terminal patient. This patient died in the 18 th month and continued to maintain her ability to ambulate and retain bowel and bladder function.
The majority of complications in our study were considered to be minor. The overall patient complication rate in our series was of 41.6%. Although it may appear high, this rate should be considered acceptable, given the special condition of the patients and the complexity of the surgical treatment needed.
Street, et al. [15], using a very similar technique, reported an overall patient complication rate of 47% with 26% of major complication. Twenty one percent of patients in their series required early reoperation.
We conclude that palliative surgery, when well indicated, results in an improvement in quality of life in patients who are ineligible for wide resection with margin. The technique presented was a safe alternative for resection and reconstruction of tumors localized in the thoracic spine.