Histological investigation of resected dura mater attached to spinal meningioma

A Retrospective Cohort Study Evaluating the Comparative Effectiveness of Unilateral Hemilaminectomy and Bilateral Laminectomy in the Resection of Spinal Meningiomas

BACKGROUND AND OBJECTIVES

The primary treatment modality for spinal meningiomas (SM) is surgical resection. In recent years, minimal invasive spine surgery has gained considerable popularity, attributing its growth to advancements in surgical technologies and improved training of surgeons. Nonetheless, the suitability and effectiveness of minimal invasive spine surgery for intradural spinal tumor resection remain a subject of debate. In this cohort study, we aimed to compare the extent of resection of the unilateral hemilaminectomy approach, a less invasive technique, with the more traditional and invasive bilateral laminectomy.

METHODS

We performed a retrospective cohort study including patients with SM who underwent surgery at our department between 1996 and 2020. Cohorts included patients who underwent tumor resection through bilateral laminectomy and patients who underwent a unilateral hemilaminectomy. The primary end point was extent of resection according to the Simpson classification.

RESULTS

Of 131 with SM, 36 had a bilateral laminectomy and 95 were operated through a unilateral hemilaminectomy. In both groups, gross total resection, Simpson grades 1 and 2, was achieved in 94.44% and 94.74%, respectively (P = .999). The neurological outcome was also comparable in both cohorts (P = .356). Both length of hospital stay and estimated blood loss were significantly lower in the unilateral cohort (P < .05).

CONCLUSION

The results of this study indicate that the unilateral hemilaminectomy yields comparable results in both oncological and neurological outcome when compared with the bilateral laminectomy. Thus, unilateral hemilaminectomy may serve as a viable and safe alternative for the surgical removal of SM.

Predictors of Neurological Worsening after Resection of Spinal Meningiomas

BACKGROUND

Due to the slow-growing nature of spinal meningiomas, they are mostly asymptomatic for a long time, and become symptomatic after the compression of the spinal cord or nerve roots. The aim of this study was to identify predictors for a poor clinical outcome after the surgical resection of spinal meningiomas and thereby to allow a preoperative identification of high-risk spinal meningiomas.

METHODS

Data acquisition was conducted as a single-center retrospective analysis. From 1 January 2004 to 31 December 2019, 121 patients who underwent surgical resection of a spinal meningioma were reviewed. Clinical and radiological data (such as tumor size, location, occupation ratio of the spinal canal, and the degree of spinal cord compression) were assessed. The functional clinical findings of the patients were recorded using the Karnofsky Performance Score, modified McCormick scale, and Frankel scale preoperatively, at discharge, and 3-6 months after surgery.

RESULTS

The mean patient age was 66 ± 13 years. A total of 104 (86%) patients were female and 17 (14%) were male. The thoracic spine (68%) was the most common location, followed by the cervical (29%) and lumbar (3%) spine. Preoperatively, 11.7% of patients were categorized as McCormick 1, 35.8% as 2, 39.2% as 3, 11.7% as 4, and 1.7% as 5. The neurological function of the patients with a functional deficit prior to surgery improved in 46% of the patients, remained unchanged in 52%, and worsened in 2% at discharge. At early follow-up, the proportions were 54%, 28%, and 5%, respectively. Preoperative Frankel scale was a significant predictor of a postoperative deterioration. Patients with Frankel score A to C preoperatively had a 9.2 times higher chance of clinical deterioration postoperatively (OR = 9.16). We found that the Frankel scale weakly correlated with the degree of spinal cord compression. In this study, other radiological parameters, such as the degree of cord compression and spinal canal occupation ratio, did not show a significant effect on the outcome.

CONCLUSIONS

Surgery of intraspinal meningiomas can be considered safe. Neurological function improves in a large proportion of patients after surgery. However, a relevant preoperative deficit according to the Frankel scale (grade A-C) was a significant predictor of a postoperative neurological deterioration.

Dural reconstruction following resection of ventral and lateral spinal cord meningiomas: Fenestrated Durotomy with Oversized Graft technique

BACKGROUND

Meningiomas, although benign, often require complete resection due to their tendency for recurrence. However, dural reconstruction poses significant challenges, especially in the case of ventral meningiomas. While some reports have highlighted the usefulness of dural reconstruction using an artificial dura mater, no studies have yet confirmed dural canal enlargement through MRI post-surgically. This study aimed to assess the effectiveness of the Fenestrated Durotomy with Oversized Graft (FDOG) technique in cases of meningiomas and other intradural extramedullary tumors and evaluated dural canal dilation through MRI after using an artificial dura mater.

METHODS

This retrospective case series included 8 patients who underwent combined resection of intradural extramedullary tumors and dural repair using the FDOG technique. An artificial dura mater larger than that resected was inserted into the dural defect resulting from complete tumor resection on the ventral or lateral side of the spinal cord. The new dura mater was secured with a single dorsal suture. The dural incision was closed using watertight sutures following standard procedure. Measurement of the extent of dural canal enlargement was achieved via pre- and postoperative MRI scans.

RESULTS

None of the patients required additional treatments or lumbar drainage. All achieved independent ambulation without complications, and imaging tests indicated satisfactory dural expansion without signs of cerebrospinal fluid leakage.

CONCLUSIONS

The proposed method for dural repair in cases involving large dural defects on the ventral or lateral side of the spinal cord was shown to be a straightforward and effective approach with minimal postoperative complications.

Radiotherapy and radiosurgery for meningiomas

Meningiomas comprise a histologically and clinically diverse set of tumors arising from the meningothelial lining of the central nervous system. In the past decade, remarkable progress has been made in deciphering the biology of these common neoplasms. Nevertheless, effective systemic or molecular therapies for meningiomas remain elusive and are active areas of preclinical and clinical investigation. Thus, standard treatment modalities for meningiomas are limited to maximal safe resection, radiotherapy, or radiosurgery. This review examines the history, clinical rationale, and future directions of radiotherapy and radiosurgery as integral and effective treatments for meningiomas.

Short-Term Results of Simpson Grade 2 Resection in Spinal Meningiomas

BACKGROUND

Spinal meningiomas are benign and slow-growing intradural tumors. Surgery is the choice of treatment. In this retrospective study, results of minimally invasive Simpson grade 2 resection and its impact on recurrence in 44 spinal meningiomas are reviewed.

METHODS

Clinical data of 44 cases who underwent surgery for spinal meningiomas between 2010 and 2020 have been reviewed retrospectively. Demographics, preoperative and postoperative clinical states, pathologic type, location of the meningioma relative to the spinal cord, resection amount of the tumor according to Simpson's grading scale, postoperative complications, recurrence rate, and correlation between preoperative and intraoperative data and recurrence were analyzed.

RESULTS

The tumor was located in the thoracic spine in 31 cases, in the cervical spine in 12 cases, and in the lumbar spine in one case. Dural attachment of tumor was ventral to the spinal cord in 15 cases, lateral to the spinal cord in 15 cases, and posterior to the spinal cord in 14 cases. All cases underwent microsurgical Simpson grade 2 resection. Two cases were recurrent and reoperated. Recurrences were observed in cases younger than 18 years old, in cervical spines and in cases with long dural tails.

CONCLUSIONS

Simpson grade 2 resection is safe and effective in spinal meningiomas. Patients younger than 18 year old, and those with cervical location and long dural tail may be under risk of recurrence after Simpson grade 2 resection.

A new concept of the fiber composition of cervical spinal dura mater: an investigation utilizing the P45 sheet plastination technique

Purpose

Few reports have been published regarding the microanatomy of the dura mater located at the craniovertebral junction (CVJ). In clinic, the precise microanatomy of the CVJ dura mater would be taken into account, for reducing surgical complications and ineffective surgical outcomes. The main objective of the present investigation was to further elucidate the fiber composition and sources of the cervical spinal dura mater.

Methods

The formalin-fixed adult head and neck specimens (n = 21) were obtained and P45 plastinated section method was utilized for the present study. The fibers of the upper cervical spinal dura mater (SDM) were examined in the P45 sagittal sections in the CVJ area. All photographic documentation was performed via a Canon EOS 7D Mark camera.

Results

The posterior wall of the SDM sac at CVJ was found to be composed of stratified fibers, which are derived from three sources: the cerebral dura mater, the occipital periosteum, and the myodural bridge (MDB). The proper layer of the cerebral dura mater passes over the brim of the foramen magnum and enters the vertebral canal to form the inner layer of the SDM, and the fibers originating from the periosteum of the brim of the foramen magnum form the middle layer. The fibers of the MDB are inserted into the SDM and form its outer layer. It was found that the total number of fibers from each origin varied in humans.

Conclusion

At the CVJ, the posterior wall of the SDM is a multi-layered structure composed of three different originated fibers. The cerebral dura mater, the periosteum located at the brim of the foramen magnum, and MDB contribute to the formation of the SDM. The present study would be beneficial to the choice of surgical approach at the CVJ and the protection of the SDB.

The surgical challenge of ossified ventrolateral spinal meningiomas: tricks and pearls for managing large ossified meningiomas of the thoracic spine

The authors present an illustrative technical note on microsurgical resection of ventrolateral completely ossified spinal meningiomas (OSMs) and a literature review of the surgical management of calcified spinal meningiomas or OSMs. These tumors are surgically demanding due to their solid consistency, especially when in a ventrolateral location with dislocation of the spinal cord. A challenging case with significant thoracic cord compression and displacement is described. Due to the firm consistency and the ventrolateral localization of the meningioma, a piecemeal resection was necessary. This could have resulted in a free-floating tumor remnant adherent to the spinal cord, impeding safe tumor resection. To avoid such a remnant, an anchoring burr hole was drilled at the border between the spinal cord and the adamantine tumor mass. Then, a microdissector was placed within the anchoring burr hole and the tumor was gently pulled laterally while drilling away the medial parts of the ossified tumor. This procedure was repeated until separation of the tumor from the spinal cord was possible and a gross-total resection (Simpson grade II) was manageable. Throughout the procedure, continuous intraoperative neurophysiological monitoring was performed.

Clinical features and prognostic factors in spinal meningioma surgery from a multicenter study

Meningiomas are benign tumors that are treated surgically. Local recurrence is likely if the dura is preserved, and en bloc tumor and dura resection (Simpson grade I) is recommended. In some cases the dura is cauterized and preserved after tumor resection (Simpson grade II). The purpose of this study was performed to analyze clinical features and prognostic factors associated with spinal meningioma, and to identify the most effective surgical treatment. The subjects were 116 patients (22 males, 94 females) with spinal meningioma who underwent surgery at seven NSG centers between 1998 and 2018. Clinical data were collected from the NSG database. Pre- and postoperative neurological status was defined using the modified McCormick scale. The patients had a mean age of 61.2 ± 14.8 years (range 19–91 years) and mean symptom duration of 11.3 ± 14.7 months (range 1–93 months). Complete resection was achieved in 108 cases (94%), including 29 Simpson grade I and 79 Simpson grade II resections. The mean follow-up period was 84.8 ± 52.7 months. At the last follow-up, neurological function had improved in 73 patients (63%), was stable in 34 (29%), and had worsened in 9 (8%). Eight patients had recurrence, and recurrence rates did not differ significantly between Simpson grades I and II in initial surgery. Kaplan–Meier analysis of recurrence-free survival showed that Simpson grade III or IV, male, and dural tail sign were significant factors associated with recurrence (P < 0.05). In conclusion, Simpson I resection is anatomically favorable for spinal meningiomas. Younger male patients with a dural tail and a high-grade tumor require close follow-up. The tumor location and feasibility of surgery can affect the surgical morbidity in Simpson I or II resection. All patients should be carefully monitored for long-term outcomes, and we recommend lifelong surveillance after surgery.

Surgical results of the resection of spinal meningioma with the inner layer of dura more than 10 years after surgery

Most spinal meningiomas arise from the thoracic dura in middle-aged and elderly women. Simpson grade 1 resection is recommended to avoid recurrence. For ventral and ventrolateral tumors, reconstruction after total dural resection is difficult, and spinal fluid leakage is likely. To overcome this concern, Saito et al. developed the technique of resecting the tumor with the inner dural layer, preserving the outer dural layer. Although meningioma rarely recurs, the recurrence period is approximately 8 years postoperatively. No studies have evaluated long-term (> 10-year) outcomes of the Saito method. Here, we report 10 cases of the Saito method with > 10-year follow-up and compare outcomes with those of other standard approaches. Twenty-nine pathology-confirmed meningioma patients underwent surgery in our department, ten with the Saito method. We investigated resection method (dura mater treatment), pathological type, and recurrence and compared pre- and postoperative clinical findings. The median follow-up was 132 months. Recurrence occurred after Simpson grades 3 and 4 resection. Simpson grades 1, 2, and the Saito method resulted in no recurrence. Neurological symptoms improved in all patients at final follow-up. This is the first report of long-term outcomes of the Saito method. The method achieved good neurological improvement with no recurrence in > 10-year follow-up.

Long-term outcomes of spinal meningioma resection with outer layer of dura preservation technique

Spinal meningioma is a common benign intradural spinal tumor. It has been reported that the local recurrence rate after surgical resection increases with longer follow-up duration. Simpson grade 1 resection could reduce the risk of recurrence, but this procedure needs dural reconstruction, which would cause cerebrospinal fluid (CSF) leakage or iatrogenic spinal cord injury. Saito et al. reported dura preservation technique to reduce the risk of CSF leakage, in which the meningioma together with the inner layer of the dura is removed and the outer layer is preserved for simple dural closure. The long-term outcomes with this technique have never been investigated. In this study, we retrospectively analyzed the data of 38 surgically treated patients (dura preservation technique, 12 patients; Simpson grade 2 resection, 26 patients) to assess the long-term recurrence rate (mean, 121.5 months; range, 60-228 months). The local recurrence rate in the dura preservation group was 8.3% (1 of 12 cases), which was similar to that in Simpson grade 2 resection group (2 of 26 cases [7.7%]). Although this case series did not indicate the significant difference in the recurrence rates between the dura preservation group and Simpson grade 2 group, we consider that this technique still has advantages for surgically less invasiveness in terms of dural reconstruction which is necessary for Simpson grade 1 and higher possibility of complete resection of tumors compared with Simpson grade 2 resection.

Spinal meningiomas: is Simpson grade II resection radical enough?

BACKGROUND

The optimal treatment for spinal meningioma is complete resection. The radicality of resection is the most important predictive factor for future tumor recurrence. Although clinical series dedicated to spinal meningiomas are relatively frequent, only a minimum of these defines the length of the required follow-up and difference in tumor recurrence in the context of Simpson grade I and II resection. Therefore, we propose reconsideration of surgical treatment and long-term follow-up based on a retrospective analysis of 84 patients who underwent Simpson grade II resection.

METHODS

The study included 84 patients operated between 1998 and 2018. Clinical symptomatology, age, sex, risk of comorbidities, spinal level, duration of symptoms, surgical resection radicality, tumor recurrence, and complications associated with treatment were recorded and evaluated.

RESULTS

We encountered the diagnosis of spinal meningioma considerably more often in women (81%) than in men (19%). The average age of all patients was 65 years. Most meningiomas were located in the thoracic spine (82%) while the rest (18%) were located in the cervical spine. The most common symptoms were motor deficit (80%) and sensation disorders (70%). Of the symptomatic patients, 71% clinically improved, 27% showed no change and 2% worsened postoperatively. The mean follow-up was 32 months (range 1-204). During this period, there was a 5% tumor recurrence rate. However, when we analyzed a subgroup of nine patients who were monitored for more than 6 years, tumor recurrence was diagnosed in 44%, all of whom were women (mean age 51 years).

CONCLUSION

Our results indicate that tumor recurrence after Simpson II resection could be significantly higher than previously thought if the follow-up is long enough, especially in younger patients. This finding suggests we consider using radical Simpson grade I resection more frequently. The study also demonstrates that after spinal meningioma surgery the patients should be followed and monitored on a long-term basis.

Anterior Clinoidal Meningiomas: Meningeal Anatomical Considerations and Surgical Implications

Objective: Surgical removal of anterior clinoidal meningiomas (ACMs) remains a challenge because of its complicated relationship with surrounding meninges, major arteries and cranial nerves. This study aims to define the meningeal structures around the anterior clinoid process (ACP) and its surgical implications.

Methods: Five dry skulls and 19 cadavers were used in the anatomical study. Cadavers were prepared as transverse, coronal, and sagittal plastinated sections, and the meningeal architecture around the ACP was studied with dissecting and confocal microscopies. The database of meningiomas in one single center was retrospectively reviewed, and the patients with ACMs were collected for clinical analysis.

Results: The superior, lateral, medial surfaces, and the tip of ACP were covered by different layers and types of meninges. The ACMs were classified into four main types based on the sites of origin, possible extending pathways following meningeal dura. In the retrospective cohort of 131 ACMs, the percentage of types I, IIa, IIb, III, and IV were 42.0% (55/131), 19.8% (26/131), 9.2% (12/131), 16.8% (22/131), and 12.2% (16/131), respectively. We found that types IIa and I had higher chances for achieving Simpson grade 1–2 resection (92.3 and 85.4%, respectively), followed by type III (54.5%) and type IV (31.3%), while type IIb showed little chance of Simpson grade 1–2 resection. Univariate and multivariate analyses revealed ACM classification and tumor size (<3 cm) to be independent risk factors for achieving more extensive resection.

Conclusion: The meningeal architecture around the ACP may guide and determine the origin and extension of ACMs. The classification based on the meningeal architecture helps to understand surgical anatomy as well as predicting surgical outcomes.

Low recurrence after Simpson grade II resection of spinal benign meningiomas in a single-institute 10-year retrospective study

The objective of this study was to more fully understand the optimal neurosurgical strategy for spinal benign meningiomas from a medium to long-term perspective. This retrospective study included a cohort of 35 patients with a diagnosis of spinal meningioma who were first operated at our institute over the past 10 years and followed-up for at least 2 years after surgery. The inclusion criterion for the study was the pathological diagnosis finally verified as benign meningioma of World Health Organization (WHO) grade 1. The average follow-up duration after surgery was 61.0 months. The location of the spinal meningioma was classified into ventral or dorsal type based on the operative video record and the preoperative MR images. The extent of resection of the spinal meningioma was carefully determined based on the Simpson grade. The average neurological condition was significantly improved at the final follow-up. Simpson grade I or II resection was achieved in 31 of 35 cases (88.6%). No Simpson grade I or II cases showed local recurrence during follow-up. Tumor recurrence was noted in 2 of 4 cases of Simpson grade IV resection. One case has been followed-up without any re-operation because of no neurological deterioration, and the other case underwent stereotactic radiosurgery. This study suggested that meticulous Simpson grade II resection of spinal benign meningiomas of WHO grade 1 may be good enough from a medium to long-term follow-up perspective, though longer follow-up is absolutely necessary.

Oncologic benefits of dural resection in spinal meningiomas: a meta-analysis of Simpson grades and recurrence rates

OBJECTIVE

While resection of the dural attachment has been shown by Simpson and others to reduce recurrence rates for intracranial meningiomas, the oncological benefit of dural resection for spinal meningiomas is less clear. The authors performed a systematic analysis of the literature, comparing recurrence rates for patients undergoing various Simpson grade resections of spinal meningiomas to better understand the role of dural resection on outcomes after resection of spinal meningiomas.

METHODS

The PubMed/Medline database was systematically searched to identify studies describing oncological and clinical outcomes after Simpson grade I, II, III, or IV resections of spinal meningiomas.

RESULTS

Thirty-two studies describing the outcomes of 896 patients were included in the analysis. Simpson grade I, grade II, and grade III/IV resections were performed in 27.5%, 64.6%, and 7.9% of cases, respectively. The risk of procedure-related complications (OR 4.75, 95% CI 1.27-17.8, p = 0.021) and new, unexpected postoperative neurological deficits (OR ∞, 95% CI NaN-∞, p = 0.009) were both significantly greater for patients undergoing Simpson grade I resections when compared with those undergoing Simpson grade II resections. Tumor recurrence was seen in 2.8%, 4.1%, and 39.4% of patients undergoing Simpson grade I, grade II, and grade III/IV resections over a mean radiographic follow-up period of 99.3 ± 46.4 months, 95.4 ± 57.1 months, and 82.4 ± 49.3 months, respectively. No significant difference was detected between the recurrence rates for Simpson grade I versus Simpson grade II resections (OR 1.43, 95% CI 0.61-3.39, p = 0.43). A meta-analysis of 7 studies directly comparing recurrence rates for Simpson grade I and II resections demonstrated a trend toward a decreased likelihood of recurrence after Simpson grade I resection when compared with Simpson grade II resection, although this trend did not reach statistical significance (OR 0.56, 95% CI 0.23-1.36, p = 0.20).

CONCLUSIONS

The results of this analysis suggest with a low level of confidence that the rates of complications and new, unexpected neurological deficits after Simpson grade I resection of spinal meningiomas are greater than those seen with Simpson grade II resections, and that the recurrence rates for Simpson grade I and grade II resections are equivalent, although additional, long-term studies are needed before reliable conclusions may be drawn.

Surgical management of spinal meningiomas: focus on unilateral posterior approach and anterior localization

OBJECTIVESpinal meningiomas (sMNGs) are relatively rare in comparison to intracranial MNGs. sMNGs localized anterior to the denticulate ligament (aMNGs) represent a surgically challenging subgroup. A high perioperative complication rate due to the need for complex surgical approaches has been described. In the present study, the authors report on their surgical experience that involves two institutions in which 207 patients underwent surgery for sMNGs. Special focus was placed on patients with aMNGs that were treated via a unilateral posterior approach (ULPA).METHODSBetween 2005 and 2017, 207 patients underwent resection of sMNGs at one of two institutions. The following characteristics were assessed: tumor size and localization, surgical approach, duration of surgery, grade of resection, peri- and postoperative complication rates, and neurological outcome. Data were compared between the subgroups of patients according to the lesion's relationship to the denticulate ligament and to surgical approach.RESULTSThe authors identified 48 patients with aMNGs, 86 patients with lateral MNGs, and 76 patients with posterior MNGs (pMNGs). Overall, 66.6% of aMNGs and 64% of pMNGs were reached via a ULPA. aMNGs that were approached via a ULPA showed reduced duration of surgery (131 vs 224 minutes, p < 0.0001) and had surgical complication rates and neurological outcomes comparable to those of lesions that were approached via a bilateral approach. No significant differences in complication rate, outcomes, and extent of resection were seen between aMNGs and pMNGs.CONCLUSIONSThe duration of surgery, extent of resection, and outcomes are comparable between aMNGs and pMNGs when removed via a ULPA. Thus, ULPA represents a safe route to achieve a gross-total resection, even in cases of aMNG.

Lumbar intraspinal microcystic/reticular schwannoma: Case report and literature review

RATIONALE

Microcystic/reticular schwannoma (MRS) is a rare histological variant of schwannoma which was initially described in 2008 with a predilection for the visceral organs. This distinct tumor had been reported to mainly affect gastrointestinal tract, subcutaneous and soft tissue, various glands and head and neck region. However, MRS involving spine is extremely rare.

PATIENT CONCERNS

The authors report the first case of MRS occurring in the lumbar (L) spinal canal of a 40-year-old male who presented with continuous pain and numbness in both feet for 2.5 years. Physical examination revealed weakness of lower extremities and hyperalgesia of both feet.

DIAGNOSES AND INTERVENTIONS

The findings of pre-operative investigation were suspicious for either a schwannoma or a spinal meningioma. Accordingly, total laminectomy, complete tumor resection, instrumentation and spinal fusion were performed. Post-operative histopathologic examination revealed a well-encapsulated neoplasm with reticular and microcystic growth pattern. Antoni A and Antoni B regions, Verocay bodies and hyalinized blood vessels were observed. And cytologic atypia, necrosis or mitosis was absent. Immunohistochemically, the tumor cells showed strong and diffuse positivity for S-100 as well as SOX 10. Therefore, a histopathological diagnosis of MRS was finally made.

OUTCOMES

The patient remains well with no evidence of recurrence at a 22-month follow-up.

LESSONS

This is the first case of MRS which is located in the L spinal canal. Awareness of this distinctive entity is helpful in preventing diagnostic pitfalls and making correct treatment strategies.

Long-term recurrence rates after the removal of spinal meningiomas in relation to Simpson grades

PURPOSE

Simpson grade II removal (coagulation of the dural attachment after gross total removal) of spinal meningioma is considered an acceptable alternative, but increased recurrence after more than 10 years has been reported. More attention must be paid to the long-term surgical outcomes after Simpson grade II removal.

METHODS

A retrospective review was performed for 20 patients (M:F = 5:15; age, 59 ± 9 years) with Simpson grade II removal (mean follow-up period, 12.9 years; range 10.0-17.5). Magnetic resonance (MR) imaging was conducted in 17 patients at 88 ± 52 months (range 12-157). During the same period, Simpson grade I removal (removal of the dural origin) was performed in 21 patients (follow-up, 89 ± 87 months; range 9-316). Radiological recurrence was defined as a visible tumor on a follow-up MR image, and clinical tumor recurrence was defined as the recurrence of symptoms.

RESULTS

At the final follow-up, neurological symptoms had improved in 16/20 patients and remained stable in 4/20. A recurrent tumor was detected in one patient due to increased back pain at 92 months postoperative, but the symptom was stable without surgery until the last follow-up (124 months). The radiological and clinical recurrence-free survival periods were 150 ± 7 months (95 % CI 136-163) and 204 ± 6 months (95 % CI 193-215), respectively. There was no recurrence after Simpson grade I removal, whereas neurological deterioration occurred in two patients after surgery.

CONCLUSIONS

Simpson grade II removal may be an alternative option if the risk of complications with Simpson grade I removal is expected to be high.

Minimally invasive surgery for benign intradural extramedullary spinal meningiomas: experience of a single institution in a cohort of elderly patients and review of the literature

Meningiomas of the spine are the most common benign intradural extramedullary lesions and account for 25%–46% of all spinal cord tumors in adults. The goal of treatment is complete surgical resection while preserving spinal stability. Usually, these lesions occur in the thoracic region and in middle-aged women. Clinical presentation is usually nonspecific and the symptoms could precede the diagnosis by several months to years, especially in older people, in whom associated age-related diseases can mask the tumor for a long time. We report a series of 30 patients, aged 70 years or more, harboring intradural extramedullary spinal meningiomas. No subjects had major contraindications to surgery. A minimally invasive approach ( hemilaminectomy and preservation of the outer dural layer) was used to remove the tumor, while preserving spinal stability and improving the watertight dural closure. We retrospectively compared the outcomes in these patients with those in a control group subjected to laminectomy or laminotomy with different dural management. In our experience, the minimally invasive approach allows the same chances of complete tumor removal, while providing a better postoperative course than in a control group.