Surgical resection of thoracic dumbbell tumors is occasionally challenging because it necessitates surgical approach to three compartments (intraspinal, foraminal, and mediastinal). Although several surgical approaches such as single or multiple staged, combined laminectomy and open thoracotomy, or single-staged posterior wide laminectomy with instrumentation have been introduced, there has been no definite standard technique until now1,2,9,11). Currently, combined posterior laminectomy and video-assisted thoracoscopic surgery (VATS) has been introduced as an alternative method to remove thoracic dumbbell tumor in several case reports5,7,10,12). Here, we describe a one-stage posterior minimal laminectomy and VATS technique as a less invasive technique to remove thoracic dumbbell tumor and discuss the technique’s usefulness and limitations.

The mean operative time was 331 minutes (range 255 to 385 min), with estimated blood loss (EBL) of 110 to 930 mL (mean, 348 mL). In six patients, the EBL was less than 400 mL. In one patient, the EBL was 930 mL because the pathological finding was unexpectedly hemangioma. Complete tumor resection was accomplished without instrumentation and postoperative instability in all patients. Postoperative complications included atelectasis and facial anhydrosis in one patient each. One day after operation, the patient with atelectasis underwent bronchoscopy and atelectasis was immediately improved. In a patient with a dumbbell tumor at T2/3, facial anhidrosis occurred on the affected side due to sympathetic trunk injury, and this conditions still persisted after two years. All patients except for one with atelectasis were ambulatory one day after operation. Final pathologic findings included schwannoma in three patients, neurofibroma in three, and hemangioma in one (Table 1). The postoperative follow-up period was 3 to 58 months (mean: 18.5 months). There was no tumor recurrence, spinal instability or pain in any patients upon final follow-up.

A 55-year-old female (Case 4) admitted to our hospital with left thoracic radiating pain. MRI revealed a dumbbell shaped tumor with a neuroforaminal extension in the left paravertebral space and posterior mediastinum at T2/3 (Fig. 3A). We decided to perform one stage minimal posterior hemilaminectomy and VATS. During posterior laminectomy, the tumor was found to not originate from the nerve root and showed unexpected bleeding during intraspinal piecemeal removal. After complete removal of the intraspinal tumor, the exiting T2 nerve root was sacrificed for tumor extraction during VATS. After posterior approach, VATS was performed through three ports and the mediastinal mass was found to be ovoid with a diameter of 3 cm diameter in thoracoscopic view and appeared to be hypervascular. The tumor was doubled with the sympathetic chain and therefore, the proximal and distal chains of tumor were divided with clips. The mediastinal portion of the mass was removed en bloc by circumferential dissection. The final diagnosis of the dumbbell tumor was hemangioma. There were no complications and only minimal hypesthesia at the right T2 dermatome (Fig. 3B).

There have been several efforts to treat thoracic dumbbell tumors. In general, a single stage posterior approach including partial laminectomy and unilateral facetectomy has been performed1,11). However, more invasive procedures are required for tumors with large intra-thoracic components, including wide incision and resection of adjacent structures (rib, transverse process and pedicle). For stabilizing the spine, spinal reconstruction with fusion instrument should be used1).

Based on Eden classification, dumbbell tumors are classified into 4 types, as follows: Type 1 is intradural and extradural; type 2 is intradural, extradural, foraminal, and paravertebral; type 3 is extradural, foraminal, and paravertebral; and Type 4 is foraminal and paravertebral6). Type 3 dumbbell tumors are usual in the thoracic spine8). In this study, all dumbbell tumors were classified into type 3 or 4. Thus, durotomy for removal of the mass was not essential in our cases.

First, partial laminectomy is performed to remove the intraspinal component of dumbbell tumors, after which open thoracotomy is conducted to remove the intrathoracic component. However, open thoracotomy requires division of one or more major muscles of the chest wall, including the latissimus dorsi, pectoralis, or serratus muscles with spreading of the ribs. To avoid invasive thoracotomy, VATS was introduced in the early 1990s3,4). Currently, VATS is applied widely in various thoracic surgeries including resection of lung or mediastinal masses. Thoracoscopic incision is less invasive, sparing division of major muscles, which results in less postoperative pain, early recovery and lower morbidity3,4). Due to the feasibility of VATS, combined laminectomy and VATS have been used to remove thoracic dumbbell tumors5,10,12). However, the combined approach for thoracic dumbbell tumor has only been reported in case reports or technical notes due to rarity of thoracic dumbbell tumor. Although our series only included seven cases, a combined approach using VATS was applied in the largest number of patients. In our cases, a combined approach was successfully performed from T2/3 to T12/L1. Considering the possible approach of VATS to T1/2, the combined approach could be applied for dumbbell tumors of all levels. However, sympathetic chain injury can occur during removal of upper thoracic tumors, and meticulous care is required.

The best advantage of combined approach is early ambulation of patients due to less invasiveness. In our cases, all patients ambulated the day after operation, except for one with atelectasis. In addition, transfusion was not required because of lesser intraoperative bleeding below 400 mL. However, a combined approach may be difficult because intraoperative bleeding can obscure the operative field and VATS enables only limited bleeding control in highly vascular tumors. In our case of hemangioma, blood loss of 500 mL occurred during piecemeal removal of the intraspinal tumor. Therefore, we recommend that preoperative tumor embolization be considered in a combined approach for highly vascular dumbbell tumors.

There is still debate regarding whether this combined approach is really less invasive. The operation time of the combined approach is 4 to 6 hours, which is similar to that of the single posterior approach with instrumentation. Risks of postoperative pulmonary complications such as atelectasis or pleural effusion always exist. Nevertheless, our opinion is that the combined approach is less invasive than a single posterior approach because it requires no spinal instrumentation, and results in less intraoperative bleeding, less postoperative pain, and early ambulation. Therefore, a combined approach is a good alternative method for removal of thoracic dumbbell tumors.

One-stage posterior minimal laminectomy and VATS are a safe and less invasive technique for removal of thoracic dumbbell tumor without instrumentation and instability. The approach could be applied for all surgical levels. This method can reduce intraoperative bleeding and postoperative pain, resulting in early ambulation and recovery. In highly vascular tumors, preoperative embolization should be considered to reduce intraoperative bleeding.