love and dodge in 1952 , first coined the term dumb - bell tumor , reporting the ingrowths of a neurogenic tumor into the spinal canal . in addition these tumors may grow extensively outside of the spinal canal and compress the paraspinal - iliopsos complexes as well as the adnexal structures . combined antero - posterior approach has been used mostly but carries the disadvantage of two - stage operation . this approach allows one - stage exposure of thoracic and lumbar spine but is a time consuming and technically demanding operation with limited application in selected cases only . we describe an alternative approach , called transparaspinal approach for one - stage removal of dumb - bell - shaped spinal tumors . this approach , developed by w. j. michelsen , provides the simplest and most direct route for resection of dumb - bell tumors . a 16-year - old male was admitted with history of low back pain radiating to left lower limb for 6 months , progressive weakness of both lower limbs for 2 month , and hesitency of micturition for 1 month . there was lower motor neuron weakness in both lower limbs with sluggish deep tendon reflexes . computed tomography ( ct ) and magnetic resonance imaging ( mri ) revealed a dumb - bell shaped tumor occupying the spinal canal and extending into the retroperitoneal space through the left intervertebral foramen between l3 and l4 . [ figure 1 ] radiological diagnosis of a lumbar dumb - bell shaped neurinoma with necrosis was made . patient was prepared for surgery and one - stage transparaspinal removal of tumor was planned . ( a ) t2w axial image showing heterogenous dumb - bell - shaped mass causing widening of lt . neural foramina with large extracanalicular component ( b ) post - gad t1w coronal image displaying heterogenously enhancing dumb - bell mass with large intracanalicular component ( > 3 cm ) , lateral displacement of left psoas muscle is seen . ( c ) and ( d ) contrast - enhanced axial and coronal ct images revealed retroperitoneal extension of the lesion . ( black arrow heads ) the patient and his relatives were counseled about operative procedure . the risk of neurological deficit from nerve root sacrifice was discussed along with possibility of incomplete resection . after field preparation a traditional vertical midline skin incision is given , supplementd by a transverse t - shaped extension at l3- l4 disc space [ figure 2a ] . a subperiosteal exposure of the spinous process , laminae and facet complex was performed bilaterally . the tumor was identified , eroding through the bony elements and embedded in left - sided paraspinal muscle complex . fascia was opened laterally directly over the tumor to the edge of paraspinal muscle complex . operative steps ( a ) t - shaped skin incision with transverse limb over l3 - 4 neural foramina ( b ) after laminectomy and unilateral facetectomy , part of tumor passing through foramina is marked with white arrow . ( c ) pictorial representation of complete tumor exposure after sectioning of paraspinal muscles and laminectomy . ( d ) after intradural excision ( part of tumor leaving through dura is marked with arrow ) . wide laminectomy was done along with left - sided facet joint removal for adequate exposure of the tumor [ figures 2b and 2c ] . unilateral single - level sacrifice of a facet in absence of deformity usually does not produce instablity . it was not possible to preserve a functioning nerve root as rootlets were embedded in capsule of tumor . sacrifice of this root rarely produces any new neurological deficit as long - standing nerve root compression lead to development of alternative pathways of innervation . the rootlets along with part of tumor passing through l3-l4 intervertebral foramina were excised in toto along with attached dura [ figure 2d ] . this portion was first internally decompressed using ultrasonic aspirator with care to avoid perforation of capsule . once a generous internal decompression was accomplished , the capsule of the tumor was mobilized . there was a well - defined surgical plane between the tumor capsule and the adjoining adnexal structure [ figures 1c and d ] . blunt dissection was performed in the surgical plane as tumor was well separated from major neurovascular structures by psoas muscle [ figures 1c and d ] . we recommend subtotal resection , if tumor capsule is densely adherent to the surrounding tissues . we performed unilateral fixation bridging removed facet using transpedicular rods and screws [ figure 2e ] . patient was discharged on 8 postoperative day and was doing well at first follow - up visit at 1 month . the risk of neurological deficit from nerve root sacrifice was discussed along with possibility of incomplete resection . the patient is placed in prone position after induction of anesthesia and endotracheal intubation . after field preparation a traditional vertical midline skin incision is given , supplementd by a transverse t - shaped extension at l3- l4 disc space [ figure 2a ] . a subperiosteal exposure of the spinous process , laminae and facet complex was performed bilaterally . the tumor was identified , eroding through the bony elements and embedded in left - sided paraspinal muscle complex . fascia was opened laterally directly over the tumor to the edge of paraspinal muscle complex . operative steps ( a ) t - shaped skin incision with transverse limb over l3 - 4 neural foramina ( b ) after laminectomy and unilateral facetectomy , part of tumor passing through foramina is marked with white arrow . ( c ) pictorial representation of complete tumor exposure after sectioning of paraspinal muscles and laminectomy . ( d ) after intradural excision ( part of tumor leaving through dura is marked with arrow ) . wide laminectomy was done along with left - sided facet joint removal for adequate exposure of the tumor [ figures 2b and 2c ] . unilateral single - level sacrifice of a facet in absence of deformity usually does not produce instablity . it was not possible to preserve a functioning nerve root as rootlets were embedded in capsule of tumor . sacrifice of this root rarely produces any new neurological deficit as long - standing nerve root compression lead to development of alternative pathways of innervation . the rootlets along with part of tumor passing through l3-l4 intervertebral foramina were excised in toto along with attached dura [ figure 2d ] . this portion was first internally decompressed using ultrasonic aspirator with care to avoid perforation of capsule . once a generous internal decompression was accomplished , the capsule of the tumor was mobilized . there was a well - defined surgical plane between the tumor capsule and the adjoining adnexal structure [ figures 1c and d ] . blunt dissection was performed in the surgical plane as tumor was well separated from major neurovascular structures by psoas muscle [ figures 1c and d ] . we recommend subtotal resection , if tumor capsule is densely adherent to the surrounding tissues . we performed unilateral fixation bridging removed facet using transpedicular rods and screws [ figure 2e ] . patient was discharged on 8 postoperative day and was doing well at first follow - up visit at 1 month . often these tumors will compress the paraspinal and iliopsoas muscle complexes as well as the adnexal structures . this approach is time consuming and has disadvantage of two stage operation with transthoracic and retropritoneal dissection . subsequently this approach has been applied for treatment of other spinal pathologies including dumb - bell spinal tumors . although this approach permits single stage removal of dumb - bell tumors in selected cases , it is time consuming and technically demanding technique , also it only allows the removal of dumb - bell tumors whose intraspinal part does not exceed 3 cm . shamji et al concluded that it is critical to deal with spinal component first by direct intraoperative after laminectomy , regardless of any large paraspinal component . it provides direct acsses to the intradural component ; hence intradural extension is no constraint for this technique . this approach is based over two concepts . first , there are minimal biomechanical consequences to complete sectioning of the unilateral paraspinal muscles . second , there is a well - defined surgical plane between the tumor capsule and the adjacent structures . it is important to assess the degree of anterior spinal involvement of the tumor , or to determine whether anterior column stability is present . the transparaspinal approach is not appropriate in cases where extensive anterior tumor dissection from spinal cord is required or where reconstruction of anterior column is required . we advocate routine use of ct scan in preoperative preparation of all the dumb - bell tumors . ct is not only superior to mri in demonstrating bony involvement , but clearly outlines the surgical plane as well [ figure 1 ] . this permits mobilization of tumor from its surrounding structures and allows complete removal of the tumor from a single posterior approach . we are of opinion that in large intradural / intraspinal tumors with cord compression and displacement , full laminectomy is safer over hemilaminectomy and protects the cord from trauma . unilateral facetectomy , though does not lead to spinal instability , can cause problems at transitional spinal region and would certainly destabilize spine in long term or lead to pain and scoliosis . after generous internal decompression of the intradural component , every attempt should be made to dissect rootlets away from the capsule . because the root may be severly attenuated from the mass effect of the tumor , it may not be possible to preserve a functioning nerve root . if sacrifice of nerve root is required , it should be done proximal to dorsal root ganglion to prevent neuroma formation . sacrifice of the root rarely produces a neurological deficit , as long - standing root compression leads to development of alternative pathways of innervations . the most difficult part of extracanalicular capsule dissection occurs at the anterior most part , as this is the last area to be exposed through the transparaspinal approach . subtotal resection of tumor capsule is recommended , where there is a significant risk of neurological or vascular injury because risk of recurrence is very low . csf leakage and neurological injury are potential complications of this technique and should be dealt in the standard manner . patients with poor nutritional status may experience wound healing difficulties , particularly if the t - shaped skin incision is used . in all such patients , various approaches have been described in literature for treatment of complex spinal dumb - bell tumors . the indications for each approach are based on the site and features of the compressive mass and neurological status of the patient . the transparaspinal approach provides rapid and direct exposure of dumb - bell spinal tumors . in selected cases
complex dumb - bell spinal tumors are challenging surgical lesions . 
 combined antero - posterior exposures have traditionally been used in their management . 
 this combined exposure has the disadvantage of a two - stage operation with transthoracic or retroperitoneal dissection . with better understanding of biomechanics of spine and evolution of microsurgical technique , 
 there has been resurgence of single stage surgeries , among which the transparaspinal exposure provides the simplest and the most direct route for resection of dumb - bell tumors . 
 a 16-year - old male was admitted with history of back pain with radiation to left lower limb for 6 months , progressive weakness of both lower limbs for two months , and hesitancy of micturition for 1 month . 
 a clinical diagnosis of cauda - conus lesion was made . 
 radiological investigations revealed a complex dumb - bell spinal tumor extending from lower part of l2-l4 vertebra , with large paraspinal extension through left l3 intervertebral foramina . 
 tumor was successfully removed in one step using a transparaspinal approach . 
 we discuss technical details of this novel approach along with limitations and possible complications .