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 . between 2009 and 2015 , one - stage posterior minimal laminectomy and vats was performed to remove thoracic dumbbell tumor in seven patients ( two men and five women ) . the mean age of the patients was 43 years ( ranged from 30 to 57 ) , and the level of tumors varied from t2/3 to t12/l1 ( table 1 ) . the first step in posterior hemilaminectomy is a posterior midline incision of 5 cm in the prone position . next , hemilaminectomy is performed preserving the minimal lateral half facet joint with a high speed drill . after the thecal sac and intraspinal tumor mass are exposed , the involved nerve root is identified . the intraspinal mass is removed by a piecemeal technique and a small amount of tumor material is sent for frozen biopsy , after which pathological findings are identified . when the thecal sac is decompressed and the involved nerve root is resected , the normal proximal nerve root remains . in most cases , thoracic dumbbell tumor does not invade the intradural space , and the normal proximal part of the nerve root can be identified . after meticulous bleeding control , the wound is closed . after the patient s position was changed to lateral decubitus , an initial 1.1 cm incision was made in the 7th8th intercostal space ( ics ) on the mid - axillary line . thoracoscope ( 30 direction and 10 mm diameter ) was introduced to inspect the pleura . the other ports were inserted through the 3rd4th ics in the anterior axillary line and 6th7th ics in the posterior axillary line to make triangular configuration . after the thoracoscope was reinserted through the port in the 3rd4th ics in anterior axillary line , the instruments were reemployed through the other ports for grasping and dissection of tissues . after the thoracoscope was reinserted through the port in the 3rd4th ics in anterior axillary line , the instruments were reemployed through the other ports for grasping and dissection of tissues . after division of the parietal pleura around the tumor , the tumor was usually dissected from the bottom , preventing injury of the intercostal artery and vein . if the intercostal artery and vein were drained to the tumor or interrupted the dissection , they were divided using endo clips . the tumor was extracted through the port in the 3rd4th ics in the anterior axillary line using an endobag ( fig . 1 ) . the tumor surface and involved nerve root , which were resected by intraspinal approach , were identified to confirm total tumor resection . between 2009 and 2015 , one - stage posterior minimal laminectomy and vats was performed to remove thoracic dumbbell tumor in seven patients ( two men and five women ) . the mean age of the patients was 43 years ( ranged from 30 to 57 ) , and the level of tumors varied from t2/3 to t12/l1 ( table 1 ) . the first step in posterior hemilaminectomy is a posterior midline incision of 5 cm in the prone position . next , hemilaminectomy is performed preserving the minimal lateral half facet joint with a high speed drill . after the thecal sac and intraspinal tumor mass are exposed , the involved nerve root is identified . the intraspinal mass is removed by a piecemeal technique and a small amount of tumor material is sent for frozen biopsy , after which pathological findings are identified . when the thecal sac is decompressed and the involved nerve root is resected , the normal proximal nerve root remains . in most cases , thoracic dumbbell tumor does not invade the intradural space , and the normal proximal part of the nerve root can be identified . after meticulous bleeding control , the wound is closed . after the patient s position was changed to lateral decubitus , an initial 1.1 cm incision was made in the 7th8th intercostal space ( ics ) on the mid - axillary line . thoracoscope ( 30 direction and 10 mm diameter ) was introduced to inspect the pleura . the other ports were inserted through the 3rd4th ics in the anterior axillary line and 6th7th ics in the posterior axillary line to make triangular configuration . after the thoracoscope was reinserted through the port in the 3rd4th ics in anterior axillary line , the instruments were reemployed through the other ports for grasping and dissection of tissues . after the thoracoscope was reinserted through the port in the 3rd4th ics in anterior axillary line , the instruments were reemployed through the other ports for grasping and dissection of tissues . after division of the parietal pleura around the tumor , the tumor was usually dissected from the bottom , preventing injury of the intercostal artery and vein . if the intercostal artery and vein were drained to the tumor or interrupted the dissection , they were divided using endo clips . the tumor was extracted through the port in the 3rd4th ics in the anterior axillary line using an endobag ( fig . 1 ) . the tumor surface and involved nerve root , which were resected by intraspinal approach , were identified to confirm total tumor resection . 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 , in one patient , the ebl was 930 ml because the pathological finding was unexpectedly hemangioma . 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 . 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 . , 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 . there were no complications and only minimal hypesthesia at the right t2 dermatome ( fig . 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 ) . 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 . 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 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 , 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 , 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 . 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 . this method can reduce intraoperative bleeding and postoperative pain , resulting in early ambulation and recovery . in highly vascular tumors ,
objectivethis study was conducted to assess the surgical results of one - stage posterior minimal laminectomy and video - assisted thoracoscopic surgery ( vats ) for the treatment of thoracic dumbbell tumor and to describe its precise technique . 
 in addition , we investigated the technique s usefulness and limitations.methodsseven cases of thoracic dumbbell tumor ( two men and five women , mean age , 43 years ) were analyzed retrospectively . 
 pathological findings included schwannoma in four patients , neurofibroma in two patients , and hemangioma in one patient . 
 the location of tumors varied from t2/3 to t12/l1 . 
 dumbbell tumors were resected by one - stage operation using posterior laminectomy followed by vats without instrumentation . 
 clinical data were reviewed.resultsthe mean follow - up period was 25 months ( range , 358 months ) , and the operative time ranged from 255 to 385 min ( mean , 331 min ) , with estimated blood loss ranging from 110 to 930 ml ( mean , 348 ml ) . 
 the tumor was completely resected without instrumentation and postoperative instability in all cases . 
 postoperative complications included atelectasis and facial anhydrosis in one case each.conclusionone-stage posterior minimal laminectomy and vats may be a safe and less invasive technique for removal of thoracic dumbbell tumor without instability . 
 this method has the advantage of early ambulation and rapid recovery because it reduces blood loss and postoperative pain .