Surgical Excition of Spinal Intradural Meningiomas through a Single-Sided Minimally Invasive Approach: Key-Hole Laminotomy

STUDY DESIGN: Eight patients who underwent surgery through a single-sided keyhole laminotomy due to intradural extramedullary (IDEM) meningiomas were retrospectively investigated. PURPOSE: To present the surgical outcomes of single-sided keyhole laminotomies aimed to excise large ventral IDEM spinal cord menengiomas. OVERVIEW OF LITERATURE: Less invasive procedures, such as laminotomies and osteoplastic laminotomies, have been previously described in the literature, but an approach that interferes with spinal stability to an even lesser extent would be more desirable. METHODS: Tumors were removed through a slit-like space between the dura and spinal cord without retraction of the spinal cord. The neurological conditions of patients were evaluated pre- and postoperatively with the Nurick grading system. Pathologic subtypes, preoperative symptom duration, tumor location on the sagittal and axial planes, and the percentage of tumor occupying the intradural space were investigated. On follow-up, magnetic resonance imaging was conducted to evaluate whether the tumor had recurred. RESULTS: All tumors were localized either ventrally or ventrolaterally. Of the spinal menengiomas, four were cervical and four were thoracic. All lesions were completely excised, and the neurological condition improved in six patients. The remaining two patients already had preoperative Nurick grades of 0, and this score was maintained postoperatively. Neither kyphotic changes nor instability developed in any patient during the follow-up period. CONCLUSIONS: Total resection of anterior and anterolateral IDEM menengiomas, without introducing new neurological deficits, can be performed by an isolated posterior approach through a single-sided keyhole laminotomy. However, this approach should be applied cautiously and with a thorough understanding of its limitations.