Minimally invasive surgery for intradural spinal meningioma: A new standard? A comparative study between minimally invasive and open approaches.

BACKGROUND: Some authors used minimally invasive surgery (MIS) in the treatment of spinal cord tumor, but these studies had a small sample sizes and mixed extra- and intra-medullary tumors, resulting in confounding biases. The objectives of the present study were to evaluate the effectiveness and safety of MIS for spinal meningioma resection in comparison with open surgery (OS). METHODS: Consecutive patients with spinal meningioma who received either MIS or OS were included. Data for extent of resection, functional outcome, postoperative morbidity and recurrence were collected. RESULTS: A total of 48 patients (with 51 spinal meningiomas) were included. Eighteen underwent MIS and 30 OS. Meningioma volume and location did not differ significantly between groups: tumors were predominantly thoracic (n=39, 76.5%) and voluminous (occupying more than 50% of the spinal canal: n=43, 84.3%). In the MIS group, patients were older (mean age: 66.5 vs. 56.4years, P=0.02) and more fragile (mean ASA score: 2.0 vs. 1.6, P=0.06). In the MIS group, the surgical procedure was shorter (mean duration: 2.07 vs. 2.56h, P=0.04), blood loss lower (mean: 252 vs. 456mL, P=0.02), and hospital stay shorter (mean: 6.6 vs. 8.1days). Surgery improved the modified McCormick scale (P<0.0001) irrespective of the surgical technique. MIS led to no significant differences in extent of resection or postoperative morbidity. Mean follow-up was 46.6 months. At last follow-up, 91.7% (n=44) of patients were free of progression; all cases of tumor progression (n=4) occurred in the OS group. CONCLUSIONS: MIS outperformed OS in the management of intradural spinal meningioma, irrespective of location and volume. MIS appears to be particularly suitable for elderly and fragile patients.

Anterior lumbar sagittal alignment after anterior or lateral interbody fusion.

PURPOSE: Anterior or lateral interbody fusion is a treatment option for lumbar disc disease. A segmental change occurs after such surgery. This study was designed to evaluate the changes in the lumbar regional alignment after a single or two-level standalone anterior or lateral interbody fusion (ALIF or LLIF). METHODS: Data from patients referred to our institution between March 2013 and November 2015 for standalone ALIF or LLIF for low-grade isthmic spondylolisthesis or degenerative discopathy were retrospectively included in our analysis. Patients with a history of spinal fusion were excluded. Global and regional alignments were analyzed pre- and postoperatively. Pelvic tilt (PT), sacral slope (SS), sagittal vertical axis (SVA), lumbar lordosis (LL), index segmental lordosis (ISL) and L4S1 lordosis were compared. Three groups according to the pelvic incidence (PI) (low, normal and high) were separately analyzed then compared. RESULTS: Forty-one women and 27 men (mean age was 46 years; range 25-66) were included. The mean follow-up was 10.8 (range 3-34 months). The patients were globally well balanced preoperatively and remained after surgery (SVA stagnated from 16.76±28.42mm to 15.97±28.20mm, P=0.75). PT and LL did not vary. L4S1 lordosis, and ISL were significantly increased respectively from 30.56±8.59 to 34.58±7.47 (P=0.0026) and from 5.94±5.25 to 12.99±5.87 (P<0.0001) at latest follow-up. CONCLUSION: Despite effective changes in the segmental lordosis at the index levels, our findings suggest that one or two-levels standalone ALIF or LLIF had no effect on the global balance and the lumbar lordosis. The three groups behaved similarly, the regional lordosis was redistributed in a better harmony (L4S1/LL ratio went up from 55% to 61%, P=0.01). STUDY TYPE: Retrospective study. LEVEL OF EVIDENCE: 4.

[Assessment of the surgeon radiation exposure during a minimally invasive TLIF: Comparison between fluoroscopy and O-arm system]. / Évaluation de l'exposition aux radiations du chirurgien lors d'un TLIF mini-invasif: comparaison entre fluoroscopie et navigation O-arm.

INTRODUCTION: Transforaminal lumbar interbody fusion with a minimally invasive approach (MIS TLIF) has become a very popular technique in the treatment of degenerative diseases of the lumbar spine, as it allows a decrease in muscle iatrogenic. However, iterative radiological controls inherent to this technique are responsible for a significant increase in exposure to ionizing radiation for the surgeon. New techniques for radiological guidance (O-arm navigation-assisted) would overcome this drawback, but this remains unproven. OBJECTIVES: To analyze the exposure of the surgeon to intraoperative X-ray during a MIS TLIF under fluoroscopy and under O-arm navigation-assisted. MATERIALS AND METHODS: This prospective study was conducted at the University Hospital of Lille from February to May 2013. Twelve patients underwent a MIS TLIF for the treatment of low-grade spondylolisthesis; six under standard fluoroscopy (group 1) and six under O-arm system (group 2). Passive dosimeters (rings and glasses) and active dosimeters for thorax were used to measure the radiation exposure of the surgeon. RESULTS: For group 1, the average time of fluoroscopy was 3.718 minutes (3.13-4.56) while no radioscopy was perform on group 2. For the first group, the average exposure dose was 12 µSv (5-20 µSv) on the thorax, 1168 µSv (510-2790 µSv) on the main hand and 179 µSv (103-486 µSv) on the lens. The exposure dose was measured zero on the second group. CONCLUSION: The maximum recommended doses can be reached, mainly for the lens. In addition to the radioprotection measures, O-arm navigation systems are safe alternatives to significantly reduce surgeon exposure.

Failed back surgery syndrome: to re-operate or not to re-operate? A retrospective review of patient selection and failures.

INTRODUCTION: Persisting pain after spine surgery remains a challenge for the patient and the pain physician. The etiology depends on age, pathology and the interval between the first and the revision surgery. In young patients who underwent initially to discectomy, the etiology of failed back surgery syndrome (FBSS) is commonly a recurrence of herniation whereas in the elderly population, who has previously undergone a spinal fusion, persisting pain might be due to secondary sagittal unbalance associated, as a consequence, to adjacent disc disease or pseudarthrosis. OBJECTIVE: To review the etiology of failed back surgery syndrome and to discuss the radiological work-up and the treatment strategies. METHODS: Retrospective analysis of 39 consecutive patients diagnosed with FBSS. For all cases, the following parameters were reviewed: original diagnosis and initial surgery, interval between the last surgery and the revision procedure, final diagnosis after revision. Treatment options were discussed. RESULTS: Twelve patients have undergone decompressive procedures and 27 had one or multilevel fusion for various back and/or leg pain. In group 1 (decompressive surgery), the mean age of patients who had a disc herniation was 42.2 years and 69 years for patients who had laminectomies for lumbar stenosis. In group 2 (fusion), the mean age was 63.3. Loss of lumbar lordosis in elderly after one or several laminectomy(ies) was found to be a cause of failure because of sagittal kyphosis and consecutive back pain. In the fused group, suboptimal correction of lumbar lordosis could generate a pseudarthrosis, proximal junctional kyphosis and persisting pain. CONCLUSION: Dealing with FBSS patients is far from simple but it corresponds to daily practice for spine surgeons. Clinical and radiological assessments should include a full diagnostic work-up focusing on sagittal balance. Surgical treatment and re-operation might be an option if a consistent source of pain is detected.

Minimally invasive percutaneous stabilization plus balloon kyphoplasty for the treatment of type A thoraco lumbar spine fractures: minimum 4 year's follow-up.

AIM: There is no consensus regarding the ideal treatment of type A thoraco-lumbar fractures. Many surgical techniques have been described but none has demonstrated its superiority over others. Recently, minimally invasive techniques have been widely used as they reduce the immediate morbidity related to the procedure. Percutaneous pedicle screw stabilization plus balloon kyphoplasty is a valuable technique, but there are only few data regarding clinical and radiological results in the long term. The purpose of this study was to report the long-term clinical and radiological outcome of patients undergoing minimally invasive management of thoracolumbar fracture in our institution. METHODS: This was a retrospective review of prospectively collected data. Between January 2006 and June 2008, 22 patients underwent short-segment percutaneous stabilization and balloon kyphoplasty for treatment of a type A fracture of the thoraco-lumbar spine. The study included 12 males and 10 females and the mean age was 50.5 years (25-75 years). The affected levels were T10 (N.=1), T11 (N.=1), T12 (N.=3), L1 (N.=9), L2 (N.=4), L3 (N.=3) and L4 (N.=1). RESULTS: The mean follow-up period was 60.9 months (50-75 months). The mean operative time was 77 min (range 55-135 min) and the bleeding was very low (<100 mL). VAS was significantly improved from 6.1 to 1.1 at last follow-up. Vertebral kyphosis decreased by 19° to 7.7° (ap<0.001) and local kyphosis was also significantly improved from 12.3° to 4.4° at last follow-up. We reported one screw misplacement that required early repositioning and 4 cement leakage, none of which was symptomatic. No patient worsened his neurological condition postoperatively. CONCLUSION: This treatment strategy is safe and effective. Clinical and radiological results seem to be stable over the time.

[Transforaminal lumbar interbody fusion: goals of the minimal invasive approach]. / Arthrodèses transforaminales: intérêts de l'abord minimal invasif.

BACKGROUND AND PURPOSE: Transforaminal lumbar interbody fusion (TLIF) is an effective technique, which can achieve a fusion rate of up to 90%. The minimally invasive approach has become increasingly popular because it is able to minimize iatrogenic soft tissue and muscle injury. Although the minimally invasive TLIF technique has gained popularity, its effectiveness compared with open TLIF has yet to be established. The authors prospectively compared the outcomes of patients who underwent mini-open TLIF with patients who underwent open TLIF. METHODS: Between 2007 and 2008, 50 patients underwent TLIF for grade 1 spondylolisthesis; 25 mini-open TLIF and 25 open TLIF. The mean age in each group was 48years, and there was no statistically significant difference between the groups. Data were collected perioperatively. Pain and functional disability were measured using a visual analogue scale (VAS) and the Oswestry disability index (ODI) at 3months, 6months, 1year and 2years. In addition, foraminal and disc height were measured at the same intervals and the fusion was evaluated at 1year on CT-scan. Soft tissue damage was evaluated by measuring the serum myoglobin and creatine phosphokinase activity. RESULTS: The mean VAS improved from 7 to 2.8 and the ODI decreased from 30/50 to 15/50 and fusion rate at 1 year was 98%. There was no statistical difference for the clinical and radiological outcomes between the groups. The mean operative time was 186min for the open group, 170min for the mini-open group (P<0.05) and the mean blood loss was 486mL for the open group and 148mL for the mini-open group (P<0.01). CONCLUSION: The mini-open TLIF procedure for symptomatic low grade spondylolisthesis is an effective option which achieves similar clinical and radiological outcomes and reduces perioperative morbidity as well as soft tissue damage.

Recent concepts in the management of thoracolumbar spine metastasis.

As patient with cancer live longer, spine metastasis is a growing problem. Untreated, it can cause pain, instability and neurologic deficit, which can severely alter the patient's ability and quality of life. When the diagnosis is established, scoring systems help the physician to best define the objective of treatment by evaluating the life expectancy. Except in rare circumstances, treatment is palliative. Over the past 2 decades, remarkable evolution in surgical techniques provided to patients valuable therapeutic options to perform circumferential decompression and stabilization of the affected level. More recently, minimally invasive techniques allowed a significant reduction of morbidity. The parallel development of stereotactic radiosurgery offers new therapeutic options in particular for patients ineligible for surgery.

A retrospective case series of 103 consecutive patients with leptomeningeal metastasis and breast cancer.

Approximately 2-5 % of patients with breast cancer (BC) develop leptomeningeal metastasis (LM). 103 consecutive patients with BC were diagnosed with LM and initially treated with intra-CSF liposomal cytarabine from 2007 to 2011 at a single institution. Correlations were determined with respect to patient characteristics and BC subtype with regard to overall survival (OS). At LM diagnosis, 61 % of patients had a 0-2 performance status (PS), the remaining 39 % were severely neurologically impaired. Regardless of PS, all patients received intra-cerebrospinal fluid (CSF) liposomal cytarabine as first-line treatment. Systemic treatment and radiotherapy were also given in 58 and 17 % of patients respectively as clinically appropriate. Second- (intra-CSF thiotepa) and third-line (intra-CSF methotrexate) treatment was administered in 24 and 6 patients respectively. Median OS was 3.8 months (range 1 day-2.8 years). In multivariate analysis, an initial combined treatment, a second-line treatment with intra-CSF thiotepa, an initial clinical response, and a non-'ER/PR/HER2 negative' BC were significantly associated with a better OS. Median OS in this heterogeneous retrospective case series was similar to that of previously observed BC patients treated with intra-CSF methotrexate suggesting intra-CSF liposomal cytarabine is a reasonable first choice therapy of BC-related LM.

Transforaminal lumbar interbody fusion: comparison between open and mini-open approaches with two years follow-up.

BACKGROUND: Transforaminal lumbar interbody fusion (TLIF) is an efficient technique which can achieve a fusion rate of up to 90%. Minimally invasive approaches have become increasingly popular because they appear to minimize iatrogenic soft tissue and muscle injury. As minimally invasive TLIF gains popularity, its effectiveness compared with open TLIF has yet to be established. OBJECTIVE: A retrospective study was performed with the aim to compare long-term outcomes of patients who underwent mini-open TLIF with those who underwent open TLIF. METHODS: This is a retrospective review of prospectively collected data. Between 2005 and 2008, 100 patients underwent TLIF for low-grade spondylolisthesis or degenerative disc disease; 60 underwent open TLIF and 40 underwent mini-open TLIF. The mean age in each group was 48 years, and there were no statistically significant differences between the groups. Data were collected perioperatively. Pain and functional disability were measured using visual analogue scale (VAS) and Oswestry disability index (ODI) at 3 months, 6 months, 1 year, and 2 years. In addition, the fusion was evaluated at 1 year on a computerized tomography (CT) scan. RESULTS: The mean VAS improved from 7.3 to 3.8 for back pain and from 7 to 2.7 for leg pain and the ODI decreased from 60 to 30% at 2 years postoperatively. The fusion rate at 1 year was 98%. There were no statistical differences for the clinical and radiological outcomes between the groups. The mean operative time was 186 minutes in the open group and 170 minutes in the mini-open group (p < 0.05) and the mean blood loss was 486 mL in the open group and 148 mL in the mini-open group (p < 0.01). CONCLUSION: The mini-open TLIF for symptomatic low-grade spondylolisthesis and degenerative disc disease is an effective option that achieves the same clinical and radiological outcomes at a minimum 2-year follow-up and reduces perioperative morbidity.

Kyphoplasty versus vertebroplasty in osteoporotic thoracolumbar spine fractures. Short-term retrospective review of a multicentre cohort of 127 consecutive patients.

BACKGROUND: Osteoporotic spine fractures induce a heavy burden in terms of both general health and healthcare costs. The objective of this multicentre study by the French Society for Spine Surgery (SFCR) was to compare outcomes after vertebroplasty and kyphoplasty in the treatment of osteoporotic thoracolumbar vertebral fractures. HYPOTHESIS: We hypothesised that differences existed between vertebroplasty and kyphoplasty, notably regarding operative time and reduction efficacy, from which criteria for patient selection might be inferred. MATERIAL AND METHODS: We conducted a retrospective multicentre review of 127 patients with Magerl Type A low-energy fractures after a fall from standing height between 2007 and 2010; 85 were managed with vertebroplasty and 42 with kyphoplasty. Age was not a selection criterion. We recorded pain intensity, time to management, operative time, kyphosis angle, wedge angle, cement leakage rate, and degree of cement filling. RESULTS: Operative time was 43 minutes with kyphoplasty and 24 minutes with vertebroplasty (P=0.0002). Both techniques relieved pain, with no significant difference. Kyphoplasty significantly improved the wedge angle, by +6°, versus +2° with vertebroplasty (P=0.002). With kyphoplasty, the volume injected was larger and cement distribution was less favourable. Leakage rates were similar. DISCUSSION: Despite the heterogeneity of our study, our data confirm the effectiveness of kyphoplasty in alleviating pain and decreasing deformities due to osteoporotic vertebral fractures. Vertebroplasty is a faster and less costly procedure that remains useful; no detectable clinical complications occur with vertebroplasty, which ensures better anchoring of the cement in the cancellous bone.

Minimally invasive management of thoraco-lumbar fractures: combined percutaneous fixation and balloon kyphoplasty.

STUDY DESIGN: Retrospective review of prospectively collected data. BACKGROUND: There is no consensus regarding the ideal treatment of thoraco-lumbar spine fractures without neurological compromise. Many surgical techniques have been described but none has proved its definite superiority. The main drawback of these procedures is directly related to the morbidity of the approach. As minimally invasive fixation combined with balloon kyphoplasty for treatment of thoraco-lumbar fractures is gaining popularity, its efficacy has yet to be established. PURPOSE: The purpose of this study is to report operative data, clinical and radiological outcomes of patients undergoing minimally invasive management of thoraco-lumbar fracture at our institutions. METHODS: Forty-one patients underwent percutaneous kyphoplasty and stabilization for treatment of single-level fracture of the thoracic or lumbar spine. All patients were neurologically intact. There were 20 males and 21 females with an average age of 50 years. RESULTS: The mean follow-up was 15 months (3-90 months). The mean operative time was 102 minutes (range 35-240 minutes) and the mean blood loss was <100mL. VAS was significantly improved from 6.7 to 0.7 at last follow-up. Vertebral kyphosis decreased by 16° to 7.8° postoperatively (P<0.001). Local kyphosis and percentage of collapse were also significantly improved from 8° to 5.6° and from 35% to 16% at last follow-up. Fifteen leaks have been identified, three of which were posterior; all remained asymptomatic. No patient worsened his or her neurological condition postoperatively. CONCLUSION: Percutaneous stabilization plus balloon kyphoplasty seems to be a safe and effective technique to manage thoraco-lumbar fractures without neurological impairment.

Endoscopic repair of anterior or middle skull base cerebrospinal fluid leaks after tumour resection.

OBJECTIVES: This study analysed the factors influencing the risk of recurrence following endoscopic repair of CSF leaks of the anterior and middle skull base after endonasal skull base tumour resection. PATIENTS AND METHODS: A retrospective review was conducted on 17 patients operated between May 2007 and December 2010 by endonasal endoscopic resection of anterior or middle skull base tumour who presented an intraoperative CSF leak. Epidemiological data (body mass index [BMI], age, gender) and type of leak (site, size) were studied. RESULTS: CSF leaks involved the roof of the ethmoid sinus (one patient), cribriform plate (three), posterolateral wall of the sphenoid sinus (six) or the sella turcica (seven). The CSF leak recurrence rate after the first endoscopic procedure was 29.4% (5/17). Failures were not influenced by gender, age, BMI or size of the leak. All recurrences involved the sella turcica or the lateral wall of the sphenoid sinus. The success rate after a second endoscopic procedure was 88.2%. CONCLUSION: Endonasal endoscopic repair of anterior and middle skull base meningeal injuries after tumour resection is a minimally invasive and effective technique. The main challenge of this method consists of ensuring effective control of the postoperative defect after tumour resection in the sphenoidal region, as this region was the only potential risk factor for recurrence identified in this study.

TSH-secreting adenoma improved with cabergoline.

TSH-secreting adenomas are rare tumors, representing only 0.5 to 2.5% of pituitary adenomas. Their main clinical characteristics include signs of thyrotoxicosis, diffuse goiter and a compressive syndrome. Biologically, free T4 and T3 serum levels are elevated, contrasting with inadequate serum TSH levels and increased alpha chains. Magnetic resonance (MR) imaging shows a pituitary tumor, the main differential diagnosis being resistance to thyroid hormones. Treatment is based on surgery, possibly associated with somatostatin analogs and radiotherapy. Though the long-term evolution of this rare pathology seems to have improved, some clinical situations are still a challenge to treat. We report one such case that was resistant to both stereotactic radiotherapy and somatostatin analogs, but surprisingly improved with cabergoline. We suggest that cabergoline should be considered as an alternative treatment in cases of pituitary adenomas that resist traditional treatments.

[Traumatic orbital encephalocele in an adult: report of one case]. / Encéphalocèle intraorbitaire post-traumatique chez un adulte: à propos d'un cas.

Orbital roof fractures after head injury is rare. Traumatic encephaloceles in the orbital cavity are even rarer, with only 24 cases published to date. We report the case of an adult with a post-traumatic orbital encephalocele. One day after a road traffic accident with head injury, the patient developed progressive pulsatile proptosis. Computed tomography and magnetic resonance imaging revealed an isolated blow-in fracture of the orbital roof with herniation of the left frontal lobe into the orbit. Neurosurgery to repair the orbital defect led to full recovery.

[Fracture luxation of the cervical spine in patients with ankylosing spondylitis: six cases]. / Fracture luxation du rachis cervical chez des patients atteints de spondylarthrite ankylosante: à propos de six cas.

BACKGROUND AND PURPOSE: Treatment of cervical spine fracture in patients with ankylosing spondylitis is difficult. Biomechanical changes related to ossified ankylosing spondylitis spine make cervical spine fractures highly unstable. They cover the entire width of the spine inducing multidirectional instability and the risk of neurological injuries. Treatment is more difficult that in the nonossified spine. Different treatments have been proposed including anterior stabilization, posterior stabilization, or both. METHODS: We reviewed retrospectively six cases of cervical fracture dislocation in patients with ankylosing spondylitis. RESULTS: There were five cases of C6C7 fracture dislocation and one case of C4C5 fracture dislocation. Four patients had neurological impairment at diagnosis. All patients underwent surgery. Two had anterior stabilization: one patient died and the other achieved bone healing. Four patients had anterior and posterior stabilization combined with a cervical brace for three months, for two and a halo cast for two, others because of persistent instability, with neurological injury in one. A neurological improvement was obtained in four patients. One patient was lost to follow-up. CONCLUSION: Surgical management of selected patients with ankylosing spondylitis and cervical spine fractures is challenging. Combined anterior and posterior stabilization should be considered for these fractures. A cervical brace must be associated with surgical treatment. With appropriate management, outcome can be favorable.

Unstable upper pediatric cervical spine injuries: report of 28 cases and review of the literature.

OBJECTIVE: Traumatic lesions of upper cervical spine are rare in children. To evaluate their experience with this lesions and factors affecting outcome, authors conducted a retrospective study of 28 cases of upper pediatric cervical spine injuries treated in the last 25 years. MATERIALS AND METHODS: To help in treatment of these lesions, we studied our series and reviewed the literature. Patients were divided into three groups: 0 to 2, 3 to 8, and 9 to 16 years, and managed according to status at presentation and type of injury. RESULTS: Seven patients were managed surgically and 21 nonsurgically (3 halo braces, 18 hard collars or molded braces). Patients in the younger age group sustained more neurological injuries than the others. In group 1, 33% present a fracture/luxation of C0/C1 or odontoid. In group 2, 80% had sustained fracture/luxations of C2. In group 3, 60% present odontoid fractures. At late follow-up review, solid fusions were demonstrated in all patients. Neurological deterioration occur in six patients. The mortality rate was 12%. Compared with other authors' report, incidence of this lesions increased but not the number of those managed surgically. CONCLUSIONS: Management must be tailored to the patient's age, neurological status, type, and level of injury. Compared with other author's experience, fusion and instrumentation procedures were used less frequently. Signs of medullary compression, significant spine deformation, dynamic instability, and age higher than 8 years are the criteria for surgery. The criteria for instability in children are different from those used in adults because the residual spinal growth is a major concern. The best treatment is therefore preventive.

[Posterior extrusion of Biocompatible Orthopaedic Polymer (BOP) graft mimicking a calcified lumbar disc herniation: case report]. / Expulsion postérieure d'un greffon de Biocompatible orthopaedic polymer (BOP) mimant une hernie discale calcifiée lombaire: à propos d'un cas.

OBJECTIVE AND IMPORTANCE: We present a case of intracanalar extrusion of a L5S1 Biocompatible Orthopaedic Polymer (BOP) graft associated with a L4L5 disc herniation 19 years after a lumbar intersomatic fusion for a L5S1 disc herniation. Radiological aspect of this complication should be recognized by neurosurgeons. CLINICAL PRESENTATION: A 55-year old man presented with a right L5 sciatic pain. Neurological examination found a severe weakness in dorsal flexion of the foot. A lumbar CT scanner disclosed aspects consistent with right L4L5 and huge calcified L5S1 lumbar disc herniation. INTERVENTION: The patient was operated via a bilateral paravertebral approach and a L5 laminectomy. A dense and extensive epidural scarring was seen. The right L4L5 herniated disc was excised. At the left L5S1 level, fibres from a BOP graft had separated into large fragments extruded into the vertebral canal through the dura. The fibres could only be removed partially because of nerve roots adherence. The patient developed postoperative cerebrospinal fluid (CSF) leakage that required a second operation for dural closure. The postoperative course was uneventful and the patient recovered the right L5 root deficit. CONCLUSION: Neurosurgeons should be aware of the radiological aspect of this complication. If it is recognized on CT scan and asymptomatic, conservative management should be proposed because of the risk of nerve roots injury or postoperative CSF leakage.

[Primitive malignant melanoma arising in a spinal nerve root. A case report]. / Tumeur mélanocytaire primitive maligne radiculaire. A propos d'un cas.

We report the fourth case of primitive malignant melanoma arising in a spinal nerve root. A 39-year-old woman complained of one-year low back pain radiating to the right thigh and knee, and loss of 7 kg. Clinical examination found moderate quadricipital amyotrophy and hypoesthesia of anterior side of the thigh. MRI study demonstrated an enlargement of right L3 root with scalloping of the L3/L4 foramen. The T1-weighted MRI images showed a tumor hyperintensity, the T2-weighted images showed tumor isointensity and mild contrast enhancement. Due to the scalloping of L3/L4 foramen with root enlargement and slow evolution (more than one year between the first symptom and surgery without clinical worsening), the initial preoperative diagnosis was L3 schwannoma. After laminoarthrectomy and dural opening, a firm black lesion, well encapsulated and involved in a dorsal spinal root, was totally removed. The tumor was composed of irregular melanocytoid cells with high proliferation index (20%). Immunohistochemistry showed melanin, HMB-45 and S100 positivity, but reticulin was negative (that eliminates malignant melanocytic schwannoma). An extensive clinical and paraclinical research of other melanotic localisation was negative. So, the final diagnosis was intradural primitive malignant melanoma. Radiotherapy was performed on the site of the tumor. Fatal pulmonary metastasis occurred 18 months after surgery. The most common tumor with root enlargement and bony scalloping is the benign schwannoma. Despite the above described radiological features, MRI characteristics (hyperintensity when images are T1-weighted) suggest a melanocytic tumor, a tumor with a high adipose component or an intratumoral bleeding. Specific MRI sequences can eliminate adipose tissue tumor, but diagnosis between melanin and methemoglobin is still difficult. According to the index of proliferation, a primitive central melanocytic lesion can be a meningeal melanocytoma (considered as benign) or a primitive malignant melanoma. These tumors show identical protein expressions in immunohistochemistry, and their prognosis is very variable (some long-term remissions are reported for malignant melanomas and fast disseminations are described for meningeal melanocytomas treated by sub-total surgery). The L3/L4 foramen scalloping is unusual for a malignant lesion with theoretic high-speed development. The other 3 patients (reported in the literature) survive more than 3 years. The histological features of malignant lesion with benign clinical features lead to interrogation upon the actual pathologic classification.