Rib tumors invading the spine were previously considered to be a significant challenge for surgical treatment due to their high rate of recurrence. However, with the development of spinal instrumentation and surgical techniques, there have been several reports of successful en bloc resection of rib tumors invading local vertebrae, resulting in a lower recurrence rate and facilitating the long-term survival of patients. Based on these previous reports, our center has begun performing sagittal surgical resection as a means of treating primary rib tumors or secondary rib metastases involving thoracic rib, with the present report intended to share our findings.
Sagittal surgical resection is a margin-based or extensive resection strategy in which whole tumors undergo resection. The present study specifically focused on cases with rib invasion of the thoracic and rib joints, but without anterior large vessel involvement. According to the WBB surgical staging system for primary bone tumors of the spine, when a tumor occupies zones 2–5 or 8–11, a sagittal resection should be performed (provided at least one zone is free of the tumor). Tomita has pointed out that TES surgery is suitable for cases of Tomita Types 3, 4, or 5 and Tomita scores of 2, or 3, while those of Tomita types 1, 2 and 6 were considered relative indications. Those of Tomita Type 7, as well as patients who cannot tolerate surgery, were considered to be contraindications for surgery[2, 6]. Combining these two surgical staging systems, we employed a multi-segmental vertebral sagittal resection approach to remove 1/3 of the vertebral body involved by a given rib tumor while retaining the remaining 2/3 of the vertebral body in order to maintain the stability of the anterior column of this vertebral body.In this study there were no instances of recurrence, with a median time to follow-up of 25.2 months. Local control in these 5 patients was therefore considered to be good after operation. These findings therefore provide evidence that this surgical approach may be appropriate and effective not only for primary rib tumors invading the spine, but also for metastatic rib tumors with spinal involvement. Sagittal surgical resection is not a formal contraindication for metastatic rib tumors invading the spine, as this approach can be conducted safely and effectively, allowing for effective local control of both locally advanced and metastatic rib tumors despite the high risk of operative mortality.
Generally speaking, the sagittal surgical resection procedure necessitates either multiple surgical approaches or a widely enlarged single posterior approach. Successful complete tumor resection necessitates extra-compartmental tumors resection according to the Enneking surgical staging system, and as a result this excision process inevitably involves important anatomical structures around the vertebral body, with a high probability of damage to important surrounding structures. Postoperative complications in patients can include chest wall paralysis, respiratory disorders, lower limb dysfunction, cerebrospinal fluid leakage, and long-term complications such as hardware fixation failure and vertebral disc degeneration. The incidence of complications has been reported to be as high as 40% following one-stage TES[7, 8]. Hence, a precise understanding of the morbidity associated with this operation is of great importance given this high complication rate. Limiting the range of resection as much as possible in a manner consistent the principles of oncology treatment will allow surgeons to reduce these complication rates in patients with rib tumors with thoracic spine involvement.
When treating rib tumors that violate the vertebral body but not the anterior large vessels, a single posterior approach-assisted lateral approach is advantageous as this makes it possible to observe the condition of the spinal cord and the large blood vessels throughout the course of the operation, thus avoiding injury to these structures. It is also important that all aspects of the surgical procedure including the length of spine which must undergo resection be fully evaluated. Studies have confirmed that bilateral segmental arterial ligation of 3 consecutive vertebral nodes can lead to a 25% reduction in blood supply to the spine, although spinal cord function is not affected. The ligation of the bilateral segmental arteries of 4 consecutive vertebral nodes, however, can cause spinal cord ischemia syndrome. The sagittal resection approach can effectively avoid the risk of spinal cord ischemia, as the vertebral blood supply is only ligated on one side of the a given segment. This surgical resection approach removes rib tumors, appropriate soft tissue, the thoracic rib joint, and the partially affected thoracic vertebrae, however 2/3 of the affected vertebral bodies remained following the operation, and the anterior column of vertebral body was not reconstructed after operation. In all cases in the present report, there were no instances of local recurrence, with a wide range of boundary resection for all patients such that all surrounding tissues with possible involvement including the pleura and nerve roots were removed.
The incidence of postoperative complications for this approach remains high, with primary complications including spinal cord nerve injury, cerebrospinal fluid leakage, and late hardware fixation failure. Through a combination of careful operative protocols aimed at minimizing the risk of these major complications and early postoperative positive symptomatic treatment, it is possible to obtain satisfactory results. For hemorrhages of the segmental blood vessels and vertebral vein plexus, segmental vascular ligation with bipolar coagulation hemostasis and gelatin sponge compression hemostasis can be employed, respectively. Injury of spinal cord and nerve root can be caused by exposing the tumor during operation, by cutting the disc, by shaking the vertebral body, or by ligating the segmental vessels. Therefore, it is necessary to avoid excessive pulling of the spinal cord and nerve root when the spinal nerve root is separated from the surrounding tissue in the course of operating. Bandiera and Yokogawa have reported incidence rates of dural rupture of 71% and 8.3% after TES operation[7, 11]. Risk factors for such rupture reportedly include: age ≥ 54 years old, preoperative radiotherapy, resection of more than 3 vertebral bodies, and intraoperative dural injury, all of which may increase the likelihood of cerebrospinal fluid leakage after operation. In all cases in the present study, less than 1/3 of each vertebral body was excised, and anterior column reconstruction of the spine was not implemented, with all being fixed by simple posterior segmental fixation. In one case, the patient experienced hardware fixation failure after operation – likely due to vertebral body instability, which increased the stress on the posterior fixation structure leading to hardware fixation failure. For the one patient in the present study that experienced cerebrospinal fluid leakage after surgery, symptoms were improved after symptomatic treatment.
This study has several limitations. For one, the sample size was very small and thus larger future studies with more patients will be essential to validate these findings. In addition, a longer follow-up period is needed to fully assess patient outcomes. Lastly, future studies should compare outcomes for sagittal resection and normal surgical procedures in a systematic manner.