Safety and efficacy of intradural extramedullary spinal tumor removal using a minimally invasive approach

Modified Unilateral Approach for Ventrally Located Spinal Tumors

Surgery on spinal tumors becomes challenging when the tumor is ventral to the spinal cord. Conventionally, we approach it posteriorly through bilateral laminectomy and rotate the cord after sectioning the dentate ligament and nerve roots. However, manipulating the cord can be hazardous, and a long bilateral laminectomy can be invasive. Meanwhile, a narrow operative field and a limited lateral viewing angle in a unilateral approach constrained the surgeon. To overcome these problems, we previously reported a technique of modified unilateral approach where we incised the skin and the fascia horizontally and placed a pair of retractors longitudinally.The current article reports our experience applying this approach in 15 patients with ventrally located spinal tumors. The approach was performed on 10 schwannomas, 2 meningiomas, and 3 others. We evaluated paraspinal muscle atrophy on postoperative magnetic resonance imaging.The modified unilateral approach provided an excellent surgical field for removing ventrally located tumors. Gross total removal was achieved in 11 patients (92% of benign tumors). No neurological complications occurred except for one case of transient weakness. We encountered no wound-related late complications such as pain or deformity. The reduction of the cross-sectional area of the paraspinal muscles on the approach side (compared to the nonapproach side) was 0.93 (95% confidence interval: 0.72-1.06), indicating 7% atrophy (statistically nonsignificant, p = 0.48).We believe this simple technique can be useful for removing spinal tumors located ventral to the spinal cord.

Pure endoscopic minimally invasive surgery with a non‑expandable tubular retractor for intradural extramedullary spinal tumors

Minimally invasive spinal surgery (MISS) for intradural extramedullary (IDEM) spinal tumors is a safe and effective surgical strategy. Currently, various tubular retractors are widely used in the MISS of IDEM spinal tumors, primarily relying on microscopic visualization. To the best of the authors' knowledge, there is no report of pure endoscopic surgery with parallel non-expandable tubular retractors for IDEM spinal lesions. The present study reports a case series of IDEM spinal tumors that were treated via pure endoscopic MISS with a parallel non-expandable tubular retractor. The extent of tumor resection was evaluated by comparing preoperative and postoperative magnetic resonance imaging (MRI). The initial and follow-up clinical conditions were assessed according to the visual analog scale for pain and the modified McCormick scale for neurological status. Postoperative MRI demonstrated that all cases had achieved a gross total resection. After the operation, the clinical symptoms of all patients were significantly improved and there were no serious postoperative complications. At the initial follow-up, the pain experienced by the patients was significantly reduced or had even disappeared, and the neurological deficit was improved by at least one grade on the modified McCormick scale. The present report indicates that pure endoscopic MISS with a parallel non-expandable tubular retractor may be an effective and safe surgical strategy for IDEM spinal tumor resection.

Laminectomy Versus Laminectomy with Fusion for Intradural Extramedullary Tumors: A Systematic Review and Meta-Analysis

OBJECTIVE

The primary objective of our systematic review and meta-analysis was to systematically compare the reported outcomes between laminectomy and laminectomy with fixation/fusion (LF) for the treatment of intradural extramedullary tumors (IDEMTs). Our secondary objective was to compare the outcomes between different laminectomy exposure techniques.

METHODS

PubMed and Embase were queried for literature on laminectomy and LF for IDEMTs. Reports of transforaminal approaches, interlaminar approaches, corpectomy, pediatrics patients, intramedullary tumors, technical studies, animal or cadaver studies, and literature reviews were excluded. The outcome measures recorded were pain, neurologic function, functional independence, cerebrospinal fluid leak, and wound infection. Where possible, the laminectomy technique (partial laminectomy [PL] vs. total laminectomy [TL]) was specified. Stata, version 17, was used for the fixed effects inverse variance meta-analysis.

RESULTS

Of 1849 reports assessed, 17 were included. The meta-analysis revealed that laminectomy (PL or TL) resulted in higher rates of postoperative sagittal instability compared with LF (odds ratio, 1.81; P < 0.001). No differences in any other postoperative outcome were observed between laminectomy and LF (P = 0.44). The systematic review also revealed no differences in postoperative pain, neurologic function, or functional independence or disability between PL and TL. Some evidence suggested that TL might result in greater rates of sagittal instability compared with PL.

CONCLUSIONS

No differences between LF, PL, or TL in pain, neurologic deficit, functional independence, cerebrospinal fluid leak, or wound infection were reported. Laminectomy had greater odds of sagittal instability compared with LF. Patients with preoperative sagittal instability requiring extensive removal of the posterior spinal column to achieve adequate resection of large tumors might benefit from LF.

Comparison of Neuroendoscopic and Microscopic Surgery for Unilateral Hemilaminectomy: Experience of a Single Institution

Objective

This study was designed to compare the safety and efficacy of unilateral hemilaminectomy conducted under complete neuroendoscopic visualization (UHNV) relative to unilateral hemilaminectomy under total microscopic visualization (UHMV) for the treatment of patients diagnosed with intraspinal tumors.

Methods

In total, 41 patients undergoing intraspinal tumor resection at Northern Jiangsu People's Hospital were included in this study, including 20 and 21 patients in the UHNV and UHMV groups, respectively. Intraoperative parameters including incision length, operative duration, number of vertebral laminae removed and intraoperative blood loss, as well as indicators of curative efficacy such as total tumor resection rates and postoperative symptom improvement rates, and safety indicators including complication rates, recurrence rates, spinal deformity rates, spinal instability incidence, and length of stay (LOS), were compared between the two groups.

Results

In contrast to the UHMV group, patients in the UHNV group had a significantly shorter incision length and decreased intraoperative blood loss (P < 0.05), while the operative duration (P > 0.05) showed no statistical difference. Although the postoperative improvement and total tumor resection rates were enhanced, the difference was not statistically significant (P > 0.05). In comparison, the bedridden time and length of stay (LOS) were significantly shortened (P < 0.05) in the UHNV group. However, there were no significant differences in recurrence, incidence of complications, spinal deformity, and spinal instability (P > 0.05).

Conclusion

Collectively, our findings indicate that UHNV is not inferior to the UHMV approach. Moreover, due to its safe and minimally invasive nature, UHNV represents a promising alternative to UHMV as a treatment for patients with intradural extramedullary tumors.

[Intraoperative ultrasound-assisted surgery of spinal tumors]

OBJECTIVE

To improve technique of intraoperative ultrasound-assisted microsurgery of spinal tumors.

MATERIAL AND METHODS

There were 68 patients with 70 spinal tumors who underwent intraoperative ultrasound-assisted resection between 2007 and 2018. Age of patients varied from 21 to 80 (mean 48.5±14.3). Intradural tumors were diagnosed in 54 (79.4%) patients (of them intramedullary in 16 (23.5%) and extramedullary in 38 (55.9%) cases). Fourteen patients (20.6%) had extradural tumors. Intraoperative ultrasound was used to determine localization, margins and structure of tumors, interrelations with neural structures, zones of dura opening and myelotomy. We also assessed quality of resection and spinal decompression.

RESULTS

In surgery of spinal tumors, intraoperative ultrasound allows to localize the tumor with 95.3% sensitivity, determine the character of its growth, shape, size and internal structure. One can also differentiate the margins of neoplasm, control accuracy of approach, select the optimal zone for dura opening and myelotomy, objectively assess spinal cord and nerve roots decompression in real-time mode. Quality of intraoperative ultrasonography images is comparable to preoperative MRI, and even exceed resolution of MR scans in some cases.

CONCLUSION

In our study, intraoperative ultrasound has proven to be a method complementing preoperative CT and MRI. This approach provides additional data in real-time mode to form a complete picture of surgical area, increase accuracy of manipulations and reduce surgical trauma.

Management of Extramedullary Intradural Spinal Tumors: The Impact of Clinical Status, Intraoperative Neurophysiological Monitoring and Surgical Approach on Outcomes in a 12-Year Double-Center Experience

Objective: Intradural Extramedullary (IDEM) tumors are usually treated with surgical excision. The aim of this study was to investigate the impact on clinical outcomes of pre-surgical clinical conditions, intraoperative neurophysiological monitoring (IONM), surgical access to the spinal canal, histology, degree of resection and intra/postoperative complications.

Methods: This is a retrospective observational study analyzing data of patients suffering from IDEM tumors who underwent surgical treatment over a 12 year period in a double-center experience. Data were extracted from a prospectively maintained database and included: sex, age at diagnosis, clinical status according to the modified McCormick Scale (Grades I-V) at admission, discharge, and follow-up, tumor histology, type of surgical access to the spinal canal (bilateral laminectomy vs. monolateral laminectomy vs. laminoplasty), degree of surgical removal, use and type of IONM, occurrence and type of intraoperative complications, use of Ultrasonic Aspirator (CUSA), radiological follow-up.

Results: A total number of 249 patients was included with a mean follow-up of 48.3 months. Gross total resection was achieved in 210 patients (84.3%) mostly in Schwannomas (45.2%) and Meningiomas (40.4%). IONM was performed in 162 procedures (65%) and D-wave was recorded in 64.2% of all cervical and thoracic locations (99 patients). The linear regression diagram for McCormick grades before and after surgery (follow-up) showed a correlation between preoperative and postoperative clinical status. A statistically significant correlation was found between absence of worsening of clinical condition at follow-up and use of IONM at follow-up (p = 0.01) but not at discharge. No associations were found between the choice of surgical approach and the extent of resection (p = 0.79), the presence of recurrence or residual tumor (p = 0.14) or CSF leakage (p = 0.25). The extent of resection was not associated with the use of IONM (p = 0.91) or CUSA (p = 0.19).

Conclusion: A reliable prediction of clinical improvement could be made based on pre-operative clinical status. The use of IONM resulted in better clinical outcomes at follow-up (not at discharge), but no associations were found with the extent of resection. The use of minimally invasive approaches such as monolateral laminectomy showed to be effective and not associated with worse outcomes or increased complications.

Cerebrospinal fluid leaks after spine tumor resection: avoidance, recognition and management

Post-operative CSF leaks are a known complication of spine surgery in general, and patients undergoing surgical intervention for spinal tumors may be particularly predisposed due to the presence of intradural tumor and a number of other factors. Post-operative CSF leaks increase morbidity, lengthen hospital stays, prolong immobilization and subject patients to a number of associated complications. Intraoperative identification of unintended durotomies and effective primary repair of dural defects is an important first step in the prevention of post-operative CSF leaks, but in patients who develop post-operative pseudomeningoceles, durocutaneous fistulae or other CSF-leak-related sequelae, early recognition and secondary intervention are paramount to preventing further CSF-leak-related complications and achieving the best patient outcomes possible. In this article, the incidence, risk factors and complications of CSF leaks after spine tumor surgery are reviewed, with an emphasis on avoidance of post-operative CSF leaks, early post-operative identification and effective secondary intervention.

Analysis of the Surgical Technique and Outcome of the Thoracic and Lumbar Intradural Spinal Tumor Excision Using Minimally Invasive Tubular Retractor System

Background:

Conventionally, intradural spinal tumor excision requires longer skin incision, bilateral subperiosteal muscle stripping, and total laminectomy, thereby decreasing the stability of the spine and increasing the morbidity. Minimally invasive surgery (MIS) for intradural spinal tumor excision preserves the posterior supporting structures of the spine in the midline and on the contralateral side and decreases morbidity and achieves the resection of the tumor.

Aims:

The aim is to analyze the surgical technique and outcome of the thoracic and lumbar intradural spinal tumor excision using minimally invasive tubular retractor system.

Patients and Methods:

A retrospective study was conducted in patients admitted with thoracic and lumbar intradural spinal tumors who had undergone tumor excision using minimally invasive tubular retractor system and satisfied the inclusion and exclusion criteria. Intradural tumors involving one or two vertebral levels were included in the study. Intramedullary spinal tumor, intradural tumor extending into intervertebral foramen, and intradural tumor involving more than two vertebral levels were excluded from the study. The study included the data of the 13 patients, who were operated between January 2017 and October 2018. The age and sex of the patients were noted. Gadolinium-enhanced magnetic resonance imaging scan and X-ray of the spine were taken in all the patients. The pre- and postoperative data analyzed include pain using visual analog scale (VAS), power using Medical Research Council (MRC) grading, myelopathy using Nurick's grade, sensory changes, and bowel and bladder symptoms. The steps involved in the surgical technique, extent of resection, intraoperative blood loss, duration of surgery, postoperative complications, duration of stay after the surgery, and postoperative X-ray were analyzed.

Results:

Out of 13 patients, one case of dorsally placed meningioma was converted to open laminectomy and excision due to nonvisualization of the spinal cord and increased bleeding from the tumor. Hence, data of the remaining 12 patients were analyzed. The histopathology of these cases was meningioma (6), schwannoma (5), and neurenteric cyst (1). There were 5 men and 7 women with age group of 27–70 years (mean: 48 years). There were 8 thoracic and 4 lumbar tumors. The duration of symptoms was 2 days to 72 months (mean: 35 months). Eight cases were predominantly occupying on the right side and 4 cases on the left side within the spinal canal. The skin incision length was 25 mm to 35 mm (mean: 28 mm). We used tubular retractors with diameter ranging from 22 mm to 30 mm (mean: 24 mm). Expandable retractors were used in 9 cases (75%) and nonexpandable in 3 cases (25%). Tubular retractor of company Jayon (India) was used in 5 cases and PITKAR (India) in 7 cases. We have not found any significant difference in the usage of both the systems. The tumor size (craniocaudal) was ranging from 9.5 mm to 38 mm (mean: 19 mm). Intraoperative blood loss was 75–200 ml (mean: 115 ml). Gross total resection was achieved in 8 cases and near-total resection in 4 cases. Dura was sutured primarily in all the cases. The dural closure was done with continuous sutures in 6 (50%) cases and interrupted in 6 (50%) cases. Polypropylene suture was used in 10 cases and polyglactin suture in 2 cases of dural closure. The authors found it easy to suture the dura using 7-0 polypropylene. Fibrin sealant was used in 9 (75%) cases. The duration of the surgery was ranging from 160 min to 390 min (mean: 260 min). Cerebrospinal fluid leak and pseudomeningocele were noted in one case. One patient developed suture site infection. VAS for pain, sensory symptoms, Nurick's grade for myelopathy, and MRC grading for power were improved in all the affected patients. Out of two patients with constipation, one patient improved and the other developed incontinence, which was recovered on follow-up after 2 weeks. Out of the 4 patients with urinary symptoms, 3 were improved. Another patient of preoperative normal micturition developed urinary retention due to exacerbation of benign prostatic hypertrophy. Postoperative X-ray showed preserved spinous process and facet joints in all cases. The duration of the hospital stay was ranging from 2 days to 11 days (mean: 6 days).

Conclusion:

Anteriorly or laterally placed intradural spinal tumors confined to the spinal canal can be excised safely and effectively using tubular retractor system, with adding the advantages of the MIS surgery. When in doubt, always convert the MIS to open surgery to avoid injury to vital structures.

[Surgical treatment of intradural extramedullary lesions by hemilaminectomy]

OBJECTIVE

To evaluate the usefulness of hemilaminectomy as a surgical approach in patients with intradural-extramedullary tumors.

METHODS

Retrospective analysis of patients in which hemilaminectomy was as surgical approach in intradural-extramedullary tumors between June 2006 and December 2015. Demographics, preoperative symptoms, imaging characteristics, intraoperative findings, histological lineage, and postsurgical complications were analyzed. The average follow-up was 48.9 months (6-120 months).

RESULTS

Fifty-three patients underwent hemilaminectomy. Tumor was located in the cervical level in 5 cases, in the dorsal level in 24, and in the lumbar region in 24 cases. Histological analysis revealed 28 neuromas, 11 meningiomas, 7 ependymomas, and 7 "multiple injuries." Total resection without postsurgical neurologic deficit was possible in 96% of the patients. There were no recurrences on follow-up.

CONCLUSION

Hemilaminectomy is an effective approach for the resection of lateralized cervicodorsal intradural-extramedullary tumors. It can also be used to treat midline lesions located in the lumbar level.

Surgical management of solitary nerve sheath tumors originating around the epiconus or conus medullaris: a retrospective case analysis based on neurological function

The objective of this retrospective case analysis was to evaluate the surgical impact on neurological functional recovery in cases of solitary spinal nerve sheath tumors (NSTs) originating around the epiconus, conus medullaris, or cauda equina and not associated with neurofibromatosis. This 10-year surgical study included 30 cases of spinal NSTs originating around the spine level of T12-L1 (epiconus-to-conus medullaris: Epi-CM group), and 15 cases of spinal NSTs originating below the spine level of L2 (cauda equina: CE group). A minimally invasive posterior unilateral approach was applied in 22 of 30 subjects in the Epi-CM group and in 14 of 15 subjects in the CE group. Total removal of the tumor was achieved in all cases except in two cases of subpial growth and foraminal extension in the Epi-CM group at the initial surgery. Functional assessment revealed satisfactory or acceptable neurological recovery in both groups. Twelve of 30 patients (40%) in the Epi-CM group demonstrated significant motor weakness of the ipsilateral leg, predominantly manifested as drop foot before surgery, and only 4 of 12 patients demonstrated complete recovery. Ten of 30 patients (33%) in the Epi-CM group demonstrated a significant disturbance of urination before surgery, and only 6 of 10 demonstrated complete recovery. No patients in the CE group demonstrated unsatisfactory recovery of leg motor weakness or urinary disturbance. The present study suggests that surgeons should be aware that spinal NSTs originating around the epiconus or conus medullaris may result in delayed or inadequate functional recovery, even after successful surgical resection of tumors.

CT and MRI Determination of Intermuscular Space within Lumbar Paraspinal Muscles at Different Intervertebral Disc Levels

Background

Recognition of the intermuscular spaces within lumbar paraspinal muscles is critically important for using the paramedian muscle-splitting approach to the lumbar spine. As such, it is important to determine the intermuscular spaces within the lumbar paraspinal muscles by utilizing modern medical imaging such as computed tomography (CT) and magnetic resonance imaging (MRI).

Methods

A total of 30 adult cadavers were studied by sectional anatomic dissection, and 60 patients were examined using CT (16 slices, 3-mm thickness, 3-mm intersection gap, n = 30) and MRI (3.0T, T2-WI, 5-mm thickness, 1-mm intersection gap, n = 30). The distances between the midline and the superficial points of the intermuscular spaces at different intervertebral disc levels were measured.

Results

Based on study of our cadavers, the mean distances from the midline to the intermuscular space between multifidus and longissimus, from intervertebral disc levels L1–L2 to L5–S1, were 0.9, 1.1, 1.7, 3.0, and 3.5 cm, respectively. Compared with the upper levels (L1–L3), the superficial location at the lower level (L4–S1) is more laterally to the midline (P<0.05). The intermuscular space between sacrospinalis and quadratus lumborum, and that between longissimus and iliocostalis did not exist at L4–S1. The intermuscular spaces in patients also varied at different levels of the lumbar spine showing a low discontinuous density in CT and a high signal in MRI. There were no significant differences between the observations in cadavers and those made using CT and MRI.

Conclusion

The intermuscular spaces within the paraspinal muscles vary at different intervertebral disc levels. Preoperative CT and MRI can facilitate selection of the muscle-splitting approach to the lumbar spine. This paper demonstrates the efficacy of medical imaging techniques in surgical planning.

Surgical management of Giant Lumbar Extradural Schwannoma: Report of 3 cases

Standard surgical approach for extradural paraspinal tumours has been through a unilateral facetectomy, inter-transverse or retroperitoneal approach. Some of these approaches destabilise the spine and consequently require a fusion procedure. Access to these tumours through a minimal access route can decrease tissue damage, fasten post-operative recovery and obviate the need for a concomitant fusion procedure. However, proper case selection and adequate pre-operative planning are important in choosing cases for a minimally invasive approach. We discuss three cases of giant extradural, paraspinal schwannomas. One case that was associated with listhesis along with the tumour situated more anteriorly and embedded in the psoas muscle was managed by lateral retroperitoneal route with simultaneous interbody graft followed by posterior interspinous stabilising device. The other two cases were managed by minimal access route using a 22mm fixed tubular retractor, one by a paramedian approach and one by far lateral approach. The technique and merits of the procedure are discussed.

Minimally invasive resection of an extradural far lateral lumbar schwannoma with zygapophyseal joint sparing: surgical nuances and literature review

Introduction. Spinal schwannomas are benign nerve sheath tumors. Completely extradural schwannomas of the lumbar spine are extremely rare lesions, accounting for only 0,7–4,2% of all spinal NSTs. Standard open approaches have been used to treat these tumors, requiring extensive muscle dissection, laminectomy, radical foraminotomy, and facetectomy. In this paper the authors present the case of a minimally invasive resection of a completely extradural schwannoma. Operative technique literature review is presented. Material & Methods. A 50-year-old woman presented with progressive complains of chronic right leg pain and paresthesia. The magnetic resonance imaging revealed a giant well-encapsulated dumbbell-shaped extradural lesion at the L3-L4 level. The patient underwent a minimally invasive gross total resection of the tumor using a tubular expandable retractor system. Results. The patient had complete resolution of radiculopathy in the immediate postoperative period and she was discharged home, neurologically intact, on the second postoperative day. Postoperative MRI demonstrated no evidence of residual tumor. At latest follow-up (18 months) the patient remains asymptomatic. Conclusion. Although challenging, this minimally invasive procedure is safe and effective, being an appropriate alternative, with many potential advantages, to the open approach.

Evaluation of hemilaminectomy use in microsurgical resection of intradural extramedullary tumors

The aim of this study was to investigate the microsurgical techniques of hemilaminectomy, used in the excision of intradural extramedullary (IDEM) tumors, and to illustrate its clinical effects. Clinical data obtained from 16 patients (seven males, nine females) with IDEM tumors, which were treated at the China-Japan Union Hospital between January 2009 and December 2011, were retrospectively analyzed. The mean age of patients was 49 years, ranging from 34-72 years. The IDEM tumors were located cervically in three patients, thoracically in four patients and at the thoracico-lumbar level in nine patients. Fourteen patients underwent hemilaminectomy, while two patients were treated with laminectomy during surgery. The clinical effect of hemilaminectomy was evaluated based on Frankel grade. The mean bleeding volume was 300 ml (range, 150-500 ml) and the mean duration of surgery was 140 min (range, 90-200 min). The maximum and minimum tumor volumes were 4×1.5×1.5 cm and 1.5×1.0×1.0 cm, respectively. Neurinoma was evident in 11 patients, meningioma in four cases and neurofibroma in one case. Three cases improved from Frankel grade B to C, five cases improved from grade C to D and seven cases improved from grade D to grade E. All patients were followed up for a period of 6-40 months, with a mean follow-up time of 23.7 months. None of the patients exhibited tumor recurrence or spinal instability. The mean bleeding volume of patients that underwent hemilaminectomy and laminectomy was 275 and 475 ml, respectively. The advantages of hemilaminectomy are minor invasion, less bleeding and retention of spinal stability. In general, hemilaminectomy for the excision of IDEM tumors has a satisfactory outcome.

The use of minimally invasive approaches to resect intradural extramedullary spinal cord tumors

AIM

To conduct a comparative analysis of outcomes in patients with extramedullary tumors operated on using a minimally invasive approach and traditional laminectomy.

MATERIAL AND METHODS

The study included 40 patients (13 males and 27 females) who underwent surgical treatment at the Department of Spinal Neurosurgery of the Burdenko Neurosurgical Institute. The mean age of patients was 47 years (range: 41-60 years). Tumors were located in the cervical, thoracic and lumbar spine. All patients were divided into two groups. In the control group, 20 patients underwent traditional laminectomy using a yard retractor or an Egorov-Freidin retractor. In the study group, 20 patients underwent hemilaminectomy using a retractor for minimally invasive surgery (Caspar and MAST Qudrant). The outcomes were evaluated 3, 6, and 12 months after surgery. The McCormik and VAS scales were used for the evaluation. MRI data were also evaluated.

RESULTS

Total tumor resection was reached in all cases. The mean surgery duration was 247 min (range: 180-320 min) for the first group and 105.25 min (range: 60-190 min) for the second one. The volume of blood loss was 297 mL (range: 100-600 mL) for the first group and 210 mL (50 to 400 mL) for the second group. The histological nature of the tumors was as follows: neurinoma, meningioma, and ependymomas of the cauda equina. The evaluation of the pain syndrome in the early postoperative period revealed that the pain syndrome intensity according to VAS was reduced in patients of the second group compared to that in patients of the first group. The evaluation using the McCormik scale revealed no obvious difference in the results between the study and control groups. MRI studies performed in the postoperative period showed no tumor recurrence.

CONCLUSION

Surgical treatment of patients with intradural extramedullary tumors can be safely and effectively performed using minimally invasive approaches. A potential reduction in surgery duration, intraoperative blood loss, the amount of anesthetic drugs and reduction in the pain syndrome in the early postoperative period allow us to conclude that, when performed by an experienced surgeon, the method of minimally invasive surgery may be an alternative to the traditional removal of an extramedullary tumor.

[Factors affecting the outcome of surgical management for extramedullary spinal cord tumors: a multicenter study]

Extramedullary spinal cord tumors (ESCTs) are relatively rare neoplasms requiring surgical treatment. This paper presents a study of outcomes in patients with ESCTs treated at Irkutsk region hospitals with different facilities.

AIM

To identify factors affecting the outcome of surgical treatment of ESCTs.

MATERIAL AND METHODS

The disease stage before surgery was evaluated according to the I.Ya. Razdol'skiy and McCormick classifications. Features and extension of the approach, the extent of blood loss, surgery duration, and the equipment used were analyzed. Treatment outcomes were assessed according to the MacNub and McCormick neurological outcome scales.

RESULTS

ESCTs were removed totally in 84 (95%) patients and subtotally in 4 (5%). Tumor recurrence was detected in 8 patients. No deaths were observed. No correlation was found between the treatment outcome, according to the McCormick scale, and factors such as gender, tumor location, histological type, tumor grade, disease duration, and type of a surgical approach and the equipment used. Factors having medium and high correlations with the disease outcome are a neurological disease phase and an initial neurological deficit: sensory deficit, r=0.32; motor deficit, r=0.33; pelvic disturbances, r=0.35; McCormick grade before surgery, r=0.74; disease phase r=0.41 (p<0.05).

CONCLUSION

The disease phase is the most significant factor affecting the outcome of surgical treatment in patients with ESCTs. Despite this, important aspects of surgical treatment of ESCT include the approach that is adequate to the tumor size and localization, as well as combination of different surgical techniques.

Primary dural repair in minimally invasive spine surgery

We describe an effective surgical technique in primary repair of the spinal dura during minimally invasive spine surgery (MISS). Objective. Minimally invasive spine surgery includes the treatment of intradural lesions, and proper closure of the dura is necessary. However, primary dural closure can be difficult due to the restricted space of MIS retractors and the availability of appropriate surgical instrumentation. Methods. We describe the use of a needle already used in the pediatric neurosurgical arena that can facilitate easier and safer closure of spinal dura through MISS retractors in two illustrative intradural cases. Results and Discussion. The primary dural closure technique is described and patient demographics are included. The instruments specifically used for the intradural closure through MIS retractor systems include (1) 4-0 Surgilon braided nylon (Covidien, Dublin, Ireland) with a CV-20 taper 1/2 circle, 10 mm diameter needle; (2) Scanlan (Saint Paul, MN, USA) dura closure set. Conclusion. Successful primary dural repair can be performed on primary and incidental durotomies during minimally invasive spinal surgery. We describe the novel use of a 10 mm diameter needle to help surgeons safely and efficiently close the dura with more ease than previously described.

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.

Minimally invasive removal of a giant extradural lumbar foraminal schwannoma

Background:

Purely extradural lumbar schwannomas are rare lesions. Resection traditionally requires an open laminectomy and ipsilateral complete facectomy. Recent reports have demonstrated safety and efficacy of removal of these tumors using mini-open access devices with expandable retractors. We report a case of a giant L3 schwannoma successfully resected through a minimally invasive approach using the non-expandable Spotlight tubular retrator (Depuy Spine).

Case Description:

A 77-year-old woman presented with a history of chronic right leg pain, paresthesias and proximal right leg weakness. Magnetic Resonance imaging (MRI) scan revealed a large dumbbell-shaped extradural foraminal lesion at the L3–L4 level with significant extraforaminal extension. The patient underwent a minimally invasive gross total resection (GTR) of the tumor using an 18-mm Spotlight tubular retractor system. Pathology confirmed the lesion to be a benign schwannoma. Postoperatively, the patient's symptoms resolved and she was discharged from the hospital on the second postoperative day. Postoperative MRI showed no residual tumor. The patient returned to normal activities after 2 weeks and remained asymptomatic with no neurological deficits at final 6 months follow-up.

Conclusion:

Giant lumbar extradural schwannomas can be safely and completely resected using minimally invasive surgery without the need for facectomy or subsequent spinal fusion.

Profiles of Spinal Cord Tumors Removed through a Unilateral Hemilaminectomy

OBJECTIVE

To present the profiles of spinal cord tumors that can be removed through a unilateral hemilaminectomy and to demonstrate its usefulness for benign spinal cord tumors that significantly occupy the spinal canal.

METHODS

From June 2004 to October 2010, 25 spinal cord tumors were approached with unilateral hemilaminectomy. We calculated the cross-sectional occupying ratio (CSOR) of tumor to spinal canal before and after the operations.

RESULTS

The locations of the tumors were intradural extramedullary in 20 cases, extradural in 2, and intramedullary in 3. The levels of the tumors were lumbar in 12, thoracic 9, and cervical 4. In all cases, the tumor was removed grossly and totally without damaging spinal cord or roots. The mean height and width of the lesions we195re 17.64 mm (3-47.5) and 12.62 mm (4-32.7), respectively. The mean CSOR was 69.40% (range, 27.8-96.9%). Postoperative neurological status showed improvement in all patients except one whose neurologic deficit remained unchanged. Postoperative spinal stability was preserved during the follow-up period (mean, 21.5 months) in all cases. Tumor recurrence did not develop during the follow-up period.

CONCLUSION

Unilateral hemilaminectomy combined with microsurgical technique provides sufficient space for the removal of diverse spinal cord tumors. The basic profiles of the spinal cord tumors which can be removed through the unilateral hemilaminectomy demonstrate its role for the surgery of the benign spinal cord tumors in various sizes.