hemangioblastomas are highly vascular tumors of the central nervous system5,6,11,14,19 ) and may develop in the cerebellum , spinal cord , spinal nerves , brain stem , thalamus and pituitary stalk3,4,17,19 ) . spinal cord hemangioblastomas are relatively rare , accounting for only 2% to 6% of all spinal cord tumors13 ) . they are primarily intradural tumors , most frequently localized at the level of the cervical and thoracic vertebrae8,11 ) . on the axial plane , the epicenters of hemangioblastomas are most commonly found in the posterior aspect of the spinal cord , in the region of the dorsal root entry zone8,9,11 ) . spinal cord hemangioblastomas may occur sporadically or in association with von hippel - lindau ( vhl ) disease2,4,8,19 ) . whereas sporadic spinal hemangioblastomas are almost always solitary lesions , vhl disease is an autosomal dominant hereditary disease that causes lesions in the central nervous system , including the cerebellum , brain stem and retina , as well as tumors in other organs , such as the kidneys , pancreas , adrenal glands , paraganglia and epididymis4,6,13,17 ) . the association between spinal cord hemangioblastomas and vhl disease is strong11 ) : approximately 20% to 45% of patients with spinal hemangioblastomas have vhl disease6,11 ) . although spinal cord hemangioblastomas have benign features , such as those associated with a world health organization ( who ) grade i classification , and classically following a slow - growing course18 ) , they may cause severe neurological consequences through a mass effect by intramedullary lesions11,14,17 ) . however , a predictor of functional outcomes and the optimal treatment strategy for spinal cord hemangioblastomas are not yet fully clarified in the literature . sporadic tumors are usually pasymptomatic at diagnosis , and these should be surgically removed11 ) . however , the decision about whether to operate or only observe is less clear in patients who have vhl disease with multiple spinal cord lesions8,15,17 ) . in this study , we reviewed our experiences with 16 patients and retrospectively analyzed the clinical and radiological findings , neurological status , surgical treatments , and postoperative outcomes . the aim of this study was to determine whether there was a correlation between preoperative neurological status and postoperative functional outcomes , and to evaluate the efficacy of the treatment strategy . to predict postoperative functional outcomes , we investigated variable factors , including clinical features , tumor findings , the extent of surgical removal , and the recurrence or progression of the disease . between june 2003 and march 2012 , 16 patients underwent microsurgical treatment for spinal cord hemangioblastomas at our institute , and their medical records and radiologic studies were analyzed retrospectively . nine patients were new cases and seven patients had a recurrence or progression of residual lesions . all patients had magnetic resonance imaging ( mri ) taken pre- and postoperatively ( fig . was performed on all patients , including a family history , abdominal and cranial imaging studies and an ophthalmological examination . a preoperative angiography ( fig . 1c ) was performed in 10 cases , and preoperative embolization was performed in three . all patients underwent surgical removal using the posterior approach , and were classified into total resection ( tr ) and subtotal resection ( str ) groups . tr is defined as complete removal of the tumor by intraoperative microsurgical findings and postoperative mri . the neurological status and functional outcomes of the patients were evaluated preoperatively , at discharge and at the last follow - up , according to the functional scale described by mccormick et al.12 ) ( table 1 ) . spss 19.0 ( spss , chicago , il , usa ) was used for statistical analysis . the non - parametric test was calculated by mann - whitney 's u test or spearman 's method . a p value of < 0.05 was considered to be statistically significant . the clinical features and radiological findings are summarized in table 2 . of the 16 patients , ranging in age from 23 to 81 years ( mean age , 45.2 years ) , the mean follow - up duration was 90 months ( range , 4 to 290 months ) . the most common presenting symptoms on admission were motor weakness ( n=8 ) and pain or paresthesia of the limbs ( n=8 ) . preoperatively , eight patients ( 50% ) showed mild focal sensory changes and were classified as mccormick grade i. five patients ( 31.3% ) were classified as grade ii , two ( 12.5% ) as grade iii , and one as grade iv . because the mean duration between the initial symptom and admission was 36.8 months ( range , 1 day to 120 months ) , clinical progression was relatively slow . the spinal cord hemangioblastomas showed a strong homogeneous enhancement on the t1-weighted mri images ( wi ) with gadolinium administration and hyper - intensity with surrounding edema , cysts or syrinxes on t2-wi . the tumors were located in the cervical spine in 5 patients , the thoracic spine in 3 patients , the cervico - thoracic junction in 2 patients , and the thoraco - lumbar junction in 2 patients , with multiple lesions in 4 cases . the mean tumor size was 22.5 mm ( range , 9.6 mm to 78.6 mm ) , excluding the four vhl cases with multiple spinal lesions . cystic components , including syrinxes and cysts , were observed in 13 cases ( 81.3% ) , and peritumoral edema was observed in all patients . all hemangioblastomas were located on the dorsal or dorso - lateral surface of the spinal cord and were removed using the posterior approach . a total of 30 operations were performed on the 16 patients ( table 3 ) . total resection of the tumor was achieved in 10 patients ( 62.5% ) , and nine were sporadic spinal hemangioblastomas . str of the tumor was performed in 6 patients ( 37.5% ) , three of whom had vhl disease . recurrence after total resection or progression of the residual mass after str was observed in eight patients , who underwent a total of 22 operations ( mean , 2.8 operations per person ) . three patients ( cases 8 , 11 , and 15 ) in the tr group ( n=10 ) had recurrences , and 5 patients ( cases 9 , 10 , 13 , 14 , and 16 ) in the str group ( n=6 ) had progression of the residual tumor and also showed progression of motor deficits . after the second surgery , the tumor recurred or progressed again in 3 patients ( cases 9 , 14 , and 16 ) . all four vhl patients ( cases 13 , 14 , 15 , and 16 ) had tumor progression and underwent serial surgeries . a syringo - subarachnoid shunt with postoperative radiation therapy was performed on one patient ( case 15 ) , but the tumor progressed with neurological deterioration . the lesion was completely removed in the second operation , but recurred again after 9 years . another operation was performed , and neurological status improved postoperatively ; however , the patient died due to an aggravated renal cell carcinoma . at the final follow - up , the initial presenting symptoms had markedly improved in 3 patients ( 18.7% , cases 8 , 13 , and 15 ) . there was no change in the neurological status of 9 patients ( 56.3% ) , but 4 patients ( 25% , cases 1 , 3 , 9 , and 11 ) were worse . the extent of resection made no statistical difference in postoperative functional outcomes ( table 4 ) . in the tr group ( n=10 ) , six patients were classified as mccormick grade i , and three were classified as grade ii ( table 5 ) . at the final follow - up , seven patients had an improved or unchanged neurological status , but the remaining three patients ( cases 1 , 3 , and 11 ) exhibited greater motor deficits ( table 4 ) . the statistical analysis revealed a notable tendency for the postoperative functional grade in the tr - group patients to be correlated with the preoperative neurological status ( rho 0.718 , p<0.019 ) . a statistical trend was observed between the patients ' age in the tr group and the postoperative functional outcomes ; however , the size of the tumor , the duration of symptoms , the incidence of recurrence , the number of operations , and presence of syrinx did not affect the postoperative functional outcomes ( table 6 ) . despite the multiple operations in the str group ( n=6 ) , a poorer neurological status was only observed in one patient with a sporadic lesion ( case 9 ) , and the other patients had either improved or had an unchanged functional status at the last follow - up ( table 4 ) . before the surgery , three patients with vhl disease had a mild to moderate degree of motor weakness , and of the three sporadic hemangioblastoma cases , two were mccormick grade i , and one was grade ii ( table 3 ) . the extent of resection ( tr or str ) was correlated with recurrent lesions or tumor progression ( table 7 ) , but the presence of recurrence , the progression of the lesion and the number of repeated surgeries were not associated with surgical functional outcomes in the str group . in the cases with recurrence or progressive disease ( n=8 ) , three patients remained stable and three cases recovered to a better status during the follow - up period . in addition , there was neither postoperative aggravation nor a poorer functional outcome in the patients with vhl disease who experienced recurrence ( table 8) . some of our cases exhibited immediate postoperative functional 
 outcomes that were different from the final follow - up results . in nine patients , the functional outcomes at the final follow - up were unchanged compared with the preoperative neurological status . however , the motor function of 4 patients ( cases 2 , 6 , 7 , and 14 ) worsened in the immediate postoperative period , but gradually improved to that of the preoperative period through active rehabilitation . two of the patients ( cases 1 and 11 ) were grade ii preoperatively , and one was grade i. the motor dysfunctions in two patients worsened to mccormick grade iii or iv in the immediate postoperative period , and these patients could not walk independently . thus , active rehabilitation was not successful in older patients , and their functional outcomes were not improved at the final follow - up . this study showed the differences between sporadic hemangioblastomas and vhl disease - related hemangioblastomas , which are summarized in table 8 . the mean age of symptom onset in patients with vhl disease was 31.3 years , in the fourth decade of life , and the mean duration between the initial symptom and admission was 42 months . there were no patients who were preoperative mccormick grade i , and the four vhl patients suffered from mild to moderate paresis . the preoperative motor dysfunctions of the patients gradually worsened , and vhl disease was diagnosed after the initial evaluation . cerebellar lesions ( n=3 ) and multiple cysts in the kidney ( n=3 ) and pancreas ( n=3 ) were commonly found in this study . total resection was achieved in only one case , with the remaining three patients undergoing a subtotal resection . after the operations , the progression of the residual tumors and neurological deterioration were noted . there were relapses of the tumors in all four vhl patients , and all of these patients underwent subsequent operations , with an average of 3.25 operations each . notably , there was neither postoperative aggravation nor a poorer functional outcome in the vhl patients with recurrence , despite the repeated surgeries . paraparesis or gait disturbance was improved postoperatively in 2 vhl patients , and the other two patients experienced unchanged functional outcomes . due to the small number of vhl disease cases , it was not statistically validated that a patient 's age , preoperative neurological status , tumor location and size , presence of a syrinx or progressive lesions or the number of resected tumors were correlated with postoperative functional outcomes . the clinical features and radiological findings are summarized in table 2 . of the 16 patients , ranging in age from 23 to 81 years ( mean age , 45.2 years ) , the mean follow - up duration was 90 months ( range , 4 to 290 months ) . the most common presenting symptoms on admission were motor weakness ( n=8 ) and pain or paresthesia of the limbs ( n=8 ) . preoperatively , eight patients ( 50% ) showed mild focal sensory changes and were classified as mccormick grade i. five patients ( 31.3% ) were classified as grade ii , two ( 12.5% ) as grade iii , and one as grade iv . because the mean duration between the initial symptom and admission was 36.8 months ( range , 1 day to 120 months ) , clinical progression was relatively slow . the spinal cord hemangioblastomas showed a strong homogeneous enhancement on the t1-weighted mri images ( wi ) with gadolinium administration and hyper - intensity with surrounding edema , cysts or syrinxes on t2-wi . the tumors were located in the cervical spine in 5 patients , the thoracic spine in 3 patients , the cervico - thoracic junction in 2 patients , and the thoraco - lumbar junction in 2 patients , with multiple lesions in 4 cases . the mean tumor size was 22.5 mm ( range , 9.6 mm to 78.6 mm ) , excluding the four vhl cases with multiple spinal lesions . cystic components , including syrinxes and cysts , were observed in 13 cases ( 81.3% ) , and peritumoral edema was observed in all patients . all hemangioblastomas were located on the dorsal or dorso - lateral surface of the spinal cord and were removed using the posterior approach . a total of 30 operations were performed on the 16 patients ( table 3 ) . total resection of the tumor was achieved in 10 patients ( 62.5% ) , and nine were sporadic spinal hemangioblastomas . str of the tumor was performed in 6 patients ( 37.5% ) , three of whom had vhl disease . recurrence after total resection or progression of the residual mass after str was observed in eight patients , who underwent a total of 22 operations ( mean , 2.8 operations per person ) . three patients ( cases 8 , 11 , and 15 ) in the tr group ( n=10 ) had recurrences , and 5 patients ( cases 9 , 10 , 13 , 14 , and 16 ) in the str group ( n=6 ) had progression of the residual tumor and also showed progression of motor deficits . after the second surgery , the tumor recurred or progressed again in 3 patients ( cases 9 , 14 , and 16 ) . all four vhl patients ( cases 13 , 14 , 15 , and 16 ) had tumor progression and underwent serial surgeries . a syringo - subarachnoid shunt with postoperative radiation therapy was performed on one patient ( case 15 ) , but the tumor progressed with neurological deterioration . the lesion was completely removed in the second operation , but recurred again after 9 years . another operation was performed , and neurological status improved postoperatively ; however , the patient died due to an aggravated renal cell carcinoma . at the final follow - up , the initial presenting symptoms had markedly improved in 3 patients ( 18.7% , cases 8 , 13 , and 15 ) . there was no change in the neurological status of 9 patients ( 56.3% ) , but 4 patients ( 25% , cases 1 , 3 , 9 , and 11 ) were worse . the extent of resection made no statistical difference in postoperative functional outcomes ( table 4 ) . in the tr group ( n=10 ) , six patients were classified as mccormick grade i , and three were classified as grade ii ( table 5 ) . at the final follow - up , seven patients had an improved or unchanged neurological status , but the remaining three patients ( cases 1 , 3 , and 11 ) exhibited greater motor deficits ( table 4 ) . the statistical analysis revealed a notable tendency for the postoperative functional grade in the tr - group patients to be correlated with the preoperative neurological status ( rho 0.718 , p<0.019 ) . a statistical trend was observed between the patients ' age in the tr group and the postoperative functional outcomes ; however , the size of the tumor , the duration of symptoms , the incidence of recurrence , the number of operations , and presence of syrinx did not affect the postoperative functional outcomes ( table 6 ) . despite the multiple operations in the str group ( n=6 ) , a poorer neurological status was only observed in one patient with a sporadic lesion ( case 9 ) , and the other patients had either improved or had an unchanged functional status at the last follow - up ( table 4 ) . before the surgery , three patients with vhl disease had a mild to moderate degree of motor weakness , and of the three sporadic hemangioblastoma cases , two were mccormick grade i , and one was grade ii ( table 3 ) . the extent of resection ( tr or str ) was correlated with recurrent lesions or tumor progression ( table 7 ) , but the presence of recurrence , the progression of the lesion and the number of repeated surgeries were not associated with surgical functional outcomes in the str group . in the cases with recurrence or progressive disease ( n=8 ) , three patients remained stable and three cases recovered to a better status during the follow - up period . in addition , there was neither postoperative aggravation nor a poorer functional outcome in the patients with vhl disease who experienced recurrence ( table 8) . some of our cases exhibited immediate postoperative functional 
 outcomes that were different from the final follow - up results . in nine patients , the functional outcomes at the final follow - up were unchanged compared with the preoperative neurological status . however , the motor function of 4 patients ( cases 2 , 6 , 7 , and 14 ) worsened in the immediate postoperative period , but gradually improved to that of the preoperative period through active rehabilitation . two of the patients ( cases 1 and 11 ) were grade ii preoperatively , and one was grade i. the motor dysfunctions in two patients worsened to mccormick grade iii or iv in the immediate postoperative period , and these patients could not walk independently . thus , active rehabilitation was not successful in older patients , and their functional outcomes were not improved at the final follow - up . this study showed the differences between sporadic hemangioblastomas and vhl disease - related hemangioblastomas , which are summarized in table 8 . the mean age of symptom onset in patients with vhl disease was 31.3 years , in the fourth decade of life , and the mean duration between the initial symptom and admission was 42 months . there were no patients who were preoperative mccormick grade i , and the four vhl patients suffered from mild to moderate paresis . the preoperative motor dysfunctions of the patients gradually worsened , and vhl disease was diagnosed after the initial evaluation . cerebellar lesions ( n=3 ) and multiple cysts in the kidney ( n=3 ) and pancreas ( n=3 ) were commonly found in this study . total resection was achieved in only one case , with the remaining three patients undergoing a subtotal resection . after the operations , the progression of the residual tumors and neurological deterioration were noted . there were relapses of the tumors in all four vhl patients , and all of these patients underwent subsequent operations , with an average of 3.25 operations each . notably , there was neither postoperative aggravation nor a poorer functional outcome in the vhl patients with recurrence , despite the repeated surgeries . paraparesis or gait disturbance was improved postoperatively in 2 vhl patients , and the other two patients experienced unchanged functional outcomes . due to the small number of vhl disease cases , it was not statistically validated that a patient 's age , preoperative neurological status , tumor location and size , presence of a syrinx or progressive lesions or the number of resected tumors were correlated with postoperative functional outcomes . generally , spinal cord hemangioblastomas are encapsulated , non - infiltrative tumors7,10,18 ) , and total removal is therefore feasible in most cases . however , the capsule of the tumor is fragile , and violation of the capsule can induce massive intraoperative bleeding10,18 ) . poor delineation of the feeding arteries and draining veins may also lead to profuse intraoperative bleeding5 ) . thus , a thorough understanding of the angio - architecture and a meticulous microsurgical technique are required to achieve total resection . in our experience of failed total resections , massive intraoperative bleeding obscured the surgical field and increased the risk of indiscriminate coagulation of the undefined vessel for hemostasis . consequently , disruption of the draining veins before identifying the tumor feeders led to more copious bleeding . aggressive dissection and coagulation in the blurred margin of the tumor induced neural tissue damage or neurological deteriorations postoperatively . hence , a small lesion remained adjacent to the vessels after the cautious control of bleeding . from this perspective , preoperative angiography is mandatory for the identification of the tumors ' feeders and the drainers1,5 ) . we performed 10 cases of preoperative angiography , which was helpful for identifying the feeders and drainers in the surgical field . furthermore , to reduce the risk of bleeding , the feeding artery should be dissected carefully before coagulation of the draining vein is performed . when possible , preoperative tumor embolization is also useful for reducing intraoperative bleeding5 ) . in our experiences with three patients , embolized tumors were more easily dissected , and intraoperative bleeding was much less than expected . according to the literature , preoperatively paretic patients have a tendency toward postoperative neurological deterioration compared with asymptomatic patients2,16,18,19 ) . these studies demonstrated that the functional outcomes at the final follow - up strongly correlated with the preoperative neurological status18,19 ) . our experience of total resection of solitary hemangioblastomas revealed a similar tendency for the postoperative functional outcome to correlate with the preoperative neurological status . in the tr group , 83% of the patients who had preoperative focal neurological deficits of mccormick grade i showed stable neurological functions after removal of the tumor . of those patients with aggravated postoperative functional outcomes , 66% had a preoperative motor weakness of mccormick grade ii . interestingly , total resection was more common in those patients who only had a focal neurological deficit of mccormick grade i , and 75% of the patients who were preoperative mccormick grade i underwent total resection of the tumors . accordingly , we assume that preoperative functional status is a predictor of the postoperative neurological outcome , and total resection may be feasible in patients who have focal neurological deficits or who are in the early stage of the natural disease course . therefore , surgery may provide favorable neurological outcomes in patients with initial mild neurological deficits who are candidates for total resection . many factors , including tumor characteristics , duration of symptoms , the presence of recurrence , and the number of surgeries were considered to be predictors of postoperative outcomes , but no further interrelationship with the functional outcomes was shown in our experiences of sporadic hemangioblastomas . however , the small sample size with a consequent lack of statistical significance was a limitation of our study . in addition , whether or not a motor deficit suggests the progressive status of an intramedullary hemangioblastoma is still unclear . this assumption is also only applicable to patients who undergo tr and have sporadic hemangioblastomas and not to those who have vhl disease . this study demonstrated that there was no statistical difference in postoperative function by subtotal resection , the presence of recurrence or progression and repeated surgeries . recurrence or tumor progression was more common in the str group than in the tr group , but the functional outcomes of the str group at the last follow - up were not inferior to those of the tr group . despite repeated surgeries , we assume that an aggressive surgical resection to achieve tr may inversely cause postoperative neurological deterioration , and the reason for favorable results in the str group may be the residual lesions , which were left behind with the intention of avoiding neural tissue damage . therefore , we can postulate that preoperative mild neurological deficit and fastidious microsurgical manipulation of the neural tissue are associated with favorable outcomes for solitary hemangioblastomas . moreover , our study showed that age over 70 years deserved much consideration as a predisposing factor for a poor functional outcome . to clarify the predictors of postoperative outcomes , further studies should be performed on a larger scale . despite the similarity in the clinical , biological , and histological features between sporadic hemangioblastomas and those associated with vhl disease , definite differences with respect to the average age at presentation , the number of tumors and the treatment strategy the mean age of symptom onset was younger , and the duration of symptoms was longer in vhl disease - related hemangioblastoma patients when compared with patients having sporadic ones . our experience demonstrated that all spinal cord hemangioblastomas associated with vhl disease were recurrent or progressive . the initial presenting symptoms were shown as a more severe degree of weakness , but there was no poorer postoperative functional outcome at the final follow - up . previously , kanno et al.4 ) reported similar results , with functional outcomes in most surgical cases of symptomatic vhl disease remaining unchanged or showing improvements after the operation . in our experience , vhl disease showed a trend in which the preoperative neurological status was not correlated with the surgical outcome , unlike sporadic spinal hemangioblastoma in the tr group . although several retrospective studies of vhl disease have indicated that preoperative neurological function , the presence of a ventral or ventro - lateral lesion , tumor size , age of onset , the presence of a syrinx , and the number of resected tumors are predictors of outcome4,9,13,19 ) , these factors were not verified in this study . as the goal of surgery in spinal hemangioblastomas associated with vhl disease is symptomatic palliation , aggressive surgical resection of the lesions should be avoided . because there is currently no curative treatment for vhl disease , generally , spinal cord hemangioblastomas are encapsulated , non - infiltrative tumors7,10,18 ) , and total removal is therefore feasible in most cases . however , the capsule of the tumor is fragile , and violation of the capsule can induce massive intraoperative bleeding10,18 ) . poor delineation of the feeding arteries and draining veins may also lead to profuse intraoperative bleeding5 ) . thus , a thorough understanding of the angio - architecture and a meticulous microsurgical technique are required to achieve total resection . in our experience of failed total resections , massive intraoperative bleeding obscured the surgical field and increased the risk of indiscriminate coagulation of the undefined vessel for hemostasis . consequently , disruption of the draining veins before identifying the tumor feeders led to more copious bleeding . aggressive dissection and coagulation in the blurred margin of the tumor induced neural tissue damage or neurological deteriorations postoperatively . hence , a small lesion remained adjacent to the vessels after the cautious control of bleeding . from this perspective , preoperative angiography is mandatory for the identification of the tumors ' feeders and the drainers1,5 ) . we performed 10 cases of preoperative angiography , which was helpful for identifying the feeders and drainers in the surgical field . furthermore , to reduce the risk of bleeding , the feeding artery should be dissected carefully before coagulation of the draining vein is performed . when possible , preoperative tumor embolization is also useful for reducing intraoperative bleeding5 ) . in our experiences with three patients , embolized tumors were more easily dissected , and intraoperative bleeding was much less than expected . according to the literature , preoperatively paretic patients have a tendency toward postoperative neurological deterioration compared with asymptomatic patients2,16,18,19 ) . these studies demonstrated that the functional outcomes at the final follow - up strongly correlated with the preoperative neurological status18,19 ) . our experience of total resection of solitary hemangioblastomas revealed a similar tendency for the postoperative functional outcome to correlate with the preoperative neurological status . in the tr group , 83% of the patients who had preoperative focal neurological deficits of mccormick grade i showed stable neurological functions after removal of the tumor . of those patients with aggravated postoperative functional outcomes , 66% had a preoperative motor weakness of mccormick grade ii . interestingly , total resection was more common in those patients who only had a focal neurological deficit of mccormick grade i , and 75% of the patients who were preoperative mccormick grade i underwent total resection of the tumors . accordingly , we assume that preoperative functional status is a predictor of the postoperative neurological outcome , and total resection may be feasible in patients who have focal neurological deficits or who are in the early stage of the natural disease course . therefore , surgery may provide favorable neurological outcomes in patients with initial mild neurological deficits who are candidates for total resection . many factors , including tumor characteristics , duration of symptoms , the presence of recurrence , and the number of surgeries were considered to be predictors of postoperative outcomes , but no further interrelationship with the functional outcomes was shown in our experiences of sporadic hemangioblastomas . however , the small sample size with a consequent lack of statistical significance was a limitation of our study . in addition , whether or not a motor deficit suggests the progressive status of an intramedullary hemangioblastoma is still unclear . this assumption is also only applicable to patients who undergo tr and have sporadic hemangioblastomas and not to those who have vhl disease . this study demonstrated that there was no statistical difference in postoperative function by subtotal resection , the presence of recurrence or progression and repeated surgeries . recurrence or tumor progression was more common in the str group than in the tr group , but the functional outcomes of the str group at the last follow - up were not inferior to those of the tr group . despite repeated surgeries , the rate of neurological deterioration was actually lower in the str group . we assume that an aggressive surgical resection to achieve tr may inversely cause postoperative neurological deterioration , and the reason for favorable results in the str group may be the residual lesions , which were left behind with the intention of avoiding neural tissue damage . therefore , we can postulate that preoperative mild neurological deficit and fastidious microsurgical manipulation of the neural tissue are associated with favorable outcomes for solitary hemangioblastomas . moreover , our study showed that age over 70 years deserved much consideration as a predisposing factor for a poor functional outcome . to clarify the predictors of postoperative outcomes despite the similarity in the clinical , biological , and histological features between sporadic hemangioblastomas and those associated with vhl disease , definite differences with respect to the average age at presentation , the number of tumors and the treatment strategy are demonstrated in this study , in conjunction with the literature6,11 ) . the mean age of symptom onset was younger , and the duration of symptoms was longer in vhl disease - related hemangioblastoma patients when compared with patients having sporadic ones . our experience demonstrated that all spinal cord hemangioblastomas associated with vhl disease were recurrent or progressive . the initial presenting symptoms were shown as a more severe degree of weakness , but there was no poorer postoperative functional outcome at the final follow - up . previously , kanno et al.4 ) reported similar results , with functional outcomes in most surgical cases of symptomatic vhl disease remaining unchanged or showing improvements after the operation . in our experience , vhl disease showed a trend in which the preoperative neurological status was not correlated with the surgical outcome , unlike sporadic spinal hemangioblastoma in the tr group . although several retrospective studies of vhl disease have indicated that preoperative neurological function , the presence of a ventral or ventro - lateral lesion , tumor size , age of onset , the presence of a syrinx , and the number of resected tumors are predictors of outcome4,9,13,19 ) , these factors were not verified in this study . as the goal of surgery in spinal hemangioblastomas associated with vhl disease is symptomatic palliation , aggressive surgical resection of the lesions should be avoided . because there is currently no curative treatment for vhl disease , we advocate the total resection of solitary spinal cord hemangioblastomas because surgery is the only effective treatment modality for this condition , especially in sporadic cases . this study indicates that postoperative functional outcomes reflect preoperative neurological deficits in totally resected hemangioblastomas . however , there is no correlation between postoperative functional outcomes and other variable factors , including tumor size or location , the extent of resection , the recurrence or progression of the lesion and the number of repeated surgeries . therefore , we conclude that preoperative focal neurological deficits and meticulous microsurgical manipulation of neural structures may be the predictors of favorable outcomes of solitary spinal cord hemangioblastomas . in addition , a non - aggressive surgical approach is the optimal strategy to preserve the neurological function in spinal cord hemangioblastomas associated with vhl disease .
objectivespinal cord hemangioblastomas are rare tumors . despite their benign , slow - growing nature 
 , they can cause severe neurological consequences . 
 the purpose of this study was to evaluate variable factors , including clinical features , tumor findings , the extent of resection , and its recurrence or progression , which determine postoperative functional outcomes.methodsthis study included sixteen patients at our institute who underwent microsurgical resection for sporadic spinal intramedullary hemangioblastomas and spinal intramedullary hemangioblastomas associated with von hippel - lindau ( vhl ) disease , between june 2003 and march 2012.resultsa total of 30 operations were performed . 
 total resection ( tr ) of the tumor was achieved in 10 patients , and subtotal resection ( str ) was achieved in 6 . 
 postoperatively , the initial presenting symptoms were improved in 18.7% of the patients and were unchanged in 56.3% , but 25% were worse . 
 stable postoperative neurological functions were found in 83% of patients with preoperative mccormick grade i , and tr was achieved in 75% of these patients . in the str group , poorer neurological status 
 was observed in one patient , despite multiple operations . 
 there were no poorer outcomes in the four cases of vhl disease . 
 various factors were analyzed , but only a correlation between the pre- and postoperative neurological status was verified in the tr - group patients.conclusionpreoperative focal neurological impairment and meticulous microsurgical manipulation may be predictors of favorable outcomes for solitary hemangioblastomas . 
 in addition , the preservation of function is more important than the extent of resection in vhl disease .