Minimally invasive removal of lumbar intradural extramedullary lesions using the interlaminar approach

Abstract

<jats:sec> <jats:title>OBJECT</jats:title> <jats:p>Posterior midline laminectomy or hemilaminectomy has been successfully applied as the standard microsurgical technique for the treatment of spinal intradural pathologies. However, the associated risks of postoperative spinal instability increase the need for subsequent fusion surgery to prevent potential long-term spinal deformity. Continuous efforts have been made to minimize injuries to the surrounding tissue resulting from surgical manipulations. The authors report here their experiences with a novel minimally invasive surgical approach, namely the interlaminar approach, for the treatment of lumbar intraspinal tumors.</jats:p></jats:sec> <jats:sec> <jats:title>METHODS</jats:title> <jats:p>A retrospective review was conducted of patients at the Second Affiliated Hospital of Zhejiang University School of Medicine who underwent minimally invasive resection of lumbar intradural-extramedullary tumors. By using an operative microscope, in addition to an endoscope when necessary, the authors were able to treat all patients with a unilateral, paramedian, bone-sparing interlaminar technique. Data including preoperative neurological status, tumor location, size, pathological diagnosis, extension of resections, intraoperative blood loss, length of hospital stay, and clinical outcomes were obtained through clinical and radiological examinations.</jats:p></jats:sec> <jats:sec> <jats:title>RESULTS</jats:title> <jats:p>Eighteen patients diagnosed with lumbar intradural-extramedullary tumors were treated from October 2013 to March 2015 by this interlaminar technique. A microscope was used in 15 cases, and the remaining 3 cases were treated using a microscope as well as an endoscope. There were 14 schwannomas, 2 ependymomas, 1 epidermoid cyst, and 1 enterogenous cyst. Postoperative radiological follow-up revealed complete removal of all the lesions and no signs of bone defects in the lamina. At clinical follow-up, 14 of the 18 patients had less pain, and patients' motor/sensory functions improved or remained normal in all cases except 1.</jats:p></jats:sec> <jats:sec> <jats:title>CONClUSIONS</jats:title> <jats:p>When meeting certain selection criteria, intradural-extramedullary lumbar tumors, especially schwannomas, can be completely and safely resected through a less-invasive interlaminar approach using a microscope, or a microscope in addition to an endoscope when necessary. This approach was advantageous because it caused even less bone destruction, resulting in better postoperative spinal stability, no need for facetectomy and fusion, and quicker functional recovery for the patients. Individualized surgical planning according to preoperative radiological findings is key to a successful microsurgical resection of these lesions through the interlaminar space.</jats:p></jats:sec>

Keyhole approaches to intradural pathologies

“…Concerning the extent of resection, only 1 tumor that was planned for complete resection remained subtotally resected. This is in line with the current literature, where resection rates of 93.0%-100% are described for minimally invasive approaches 21,26,28 and 70.5%-88.5% for open posterior approaches. 1,21,29,30 These rates may be attributed to preoperative selection; if large tumors that are difficult to fully resect are not approached in a minimally invasive way from the start, lower rates of resection would be expected in the open approaches.…”

“…In our cohort, interlaminar approaches were associated with a significantly lower overall rate of surgery-related complications (9.6% vs 19.1%, p < 0.01) compared with extended open surgery (with laminectomy, laminotomy, or hemilaminectomy), indicating superiority of our keyhole approach for selected patients. Our results are comparable to results in the current literature where Zhu et al 28 discussed decreased hospitalization for patients with interlaminar approaches, reporting a mean length of stay of 13 days to which our finding of 9 days compares favorably. Laminectomies, in comparison, were frequently reported with hospital stays of 7-27 days.…”

“…Subtotal resection of the extraforaminal tumor mass may also be an option with subsequent surgery using a lateral approach. In all other cases a minimally invasive approach 28 should be attempted, with a plan to switch to hemilaminectomy as the larger approach or even complete laminectomy if resection would otherwise remain insufficient. A number of smaller approaches have been introduced to reduce the above-described complications of laminectomy.…”

“…Interlaminar approaches have the advantage of avoiding extensive resection of the facet joint. We made a special effort to preserve the joint capsule during surgery, only reducing the laminae for tumor exposure, which has been shown by Zhu et al 28 to facilitate rapid recovery and preserve spinal stability. Compared with an endoscopic approach, intraoperative visibility and maneuvering options are increased and dural closure may be safely achieved with suturing and fibrin adhesives and confirmed under the microscope.…”

Endoscopic Management of Spinal Intradural Extramedullary Tumors

“…[1][2][3][4][5] A microscope 6 or endoscope 7 has been used recently in such cases. Minimally invasive surgical (MIS) approaches using expandable or nonexpandable tubular retractor 8 or interlaminar approaches 9 have been described to reduce trauma-related instability with comparable outcome. Unilateral hemilaminectomy for intradural tumors using endoscopic assistance has been used successfully for intradural spinal tumors with preservation of musculoligamentous attachments and posterior bony elements.…”