title: Minimally invasive removal of lumbar intradural extramedullary lesions using the interlaminar approach.
abstract: OBJECT 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. METHODS 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. RESULTS 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. CONClUSIONS 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.
authors.affiliation: Department of Neurosurgery, Second Affiliated Hospital of Zhejiang University School of Medicine, Hangzhou;
authors.forename: Yong-Jian
authors.initials: YJ
authors.lastname: Zhu
authors.affiliation: Department of Neurosurgery, Second Affiliated Hospital of Zhejiang University School of Medicine, Hangzhou;
authors.forename: Guang-Yu
authors.initials: GY
authors.lastname: Ying
authors.affiliation: Department of Neurosurgery, Second Affiliated Hospital of Zhejiang University School of Medicine, Hangzhou;
authors.forename: Ai-Qin
authors.initials: AQ
authors.lastname: Chen
authors.affiliation: Department of Physiology, Zhejiang University School of Medicine, Hangzhou; and.
authors.forename: Lin-Lin
authors.initials: LL
authors.lastname: Wang
authors.affiliation: Department of Neurosurgery, Second Affiliated Hospital of Zhejiang University School of Medicine, Hangzhou;
authors.forename: Dan-Feng
authors.initials: DF
authors.lastname: Yu
authors.affiliation: Department of Neurosurgery, Second Affiliated Hospital of Zhejiang University School of Medicine, Hangzhou;
authors.forename: Liang-Liang
authors.initials: LL
authors.lastname: Zhu
authors.affiliation: Department of Neurosurgery, Second Affiliated Hospital of Zhejiang University School of Medicine, Hangzhou;
authors.forename: Yu-Cheng
authors.initials: YC
authors.lastname: Ren
authors.affiliation: Department of Neurosurgery, Second Affiliated Hospital of Zhejiang University School of Medicine, Hangzhou;
authors.forename: Chen
authors.initials: C
authors.lastname: Wang
authors.affiliation: Department of Neurosurgery, Second Affiliated Hospital of Zhejiang University School of Medicine, Hangzhou;
authors.forename: Peng-Cheng
authors.initials: PC
authors.lastname: Wu
authors.affiliation: Department of Neurosurgery, Second Affiliated Hospital of Zhejiang University School of Medicine, Hangzhou;
authors.forename: Ying
authors.initials: Y
authors.lastname: Yao
authors.affiliation: Department of Neurosurgery, Ningbo No. 2 Hospital, Ningbo, China.
authors.forename: Fang
authors.initials: F
authors.lastname: Shen
authors.affiliation: Department of Neurosurgery, Second Affiliated Hospital of Zhejiang University School of Medicine, Hangzhou;
authors.forename: Jian-Min
authors.initials: JM
authors.lastname: Zhang
mesh_terms: D000328:Adult; D000368:Aged; D017586:Diskectomy / Q000379:methods*; D004806:Ependymoma / Q000601:surgery; D005260:Female; D006801:Humans; D008161:Lumbosacral Region / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D019060:Minimally Invasive Surgical Procedures / Q000379:methods*; D009442:Neurilemmoma / Q000601:surgery; D012189:Retrospective Studies; D013120:Spinal Cord Neoplasms / Q000473:pathology / Q000601:surgery*; D016896:Treatment Outcome
keywords: ASIA = American Spinal Injury Association; CISS = constructive interference in steady state; GTR = gross-total resection; VAS = visual analog scale; VRT = volume-rendering technique; endoscope; interlaminar approach; lumbar schwannomas; microscope; minimally invasive