When a dermatopathologist encounters the ultra-rare: A case series of superficial soft tissue/cutaneous myxopapillary ependymomas.

Myxopapillary ependymoma (MPE) is an uncommon variant of ependymoma, almost exclusively seen in conus medullaris or filum terminale. MPE can be diagnostically challenging, especially when arising extra-axially. Here we report 5 cases of superficial soft tissue/cutaneous MPE, identified across three tertiary institutions. All patients were female and three of them (3/5, 60%) were children (median age 11 years, range 6-58 years). The tumors presented as slow-growing masses of the sacrococcygeal subcutaneous soft tissues, occasionally identified after minor trauma and clinically favored to be pilonidal sinuses. Imaging showed no neuraxis connection. Macroscopically, tumors were well-circumscribed, lobulated, and solid and microscopically they exhibited typical histopathology of MPE, at least focally. Two of the tumors (2/5, 40%) showed predominantly solid or trabecular architecture with greater cellular pleomorphism, scattered giant cells, and increased mitotic activity. All tumors (5/5, 100%) showed strong diffuse immunohistochemical expression of GFAP. One tumor clustered at the category "ependymoma, myxopapillary" by methylome analysis. Two patients (2/5, 40%) had local recurrence at 8 and 30 months after the initial surgery. No patients developed metastases during the follow-up period (median 60 months, range 6-116 months). Since a subset of extra-axial MPEs behaves more aggressively, timely and accurate diagnosis is of paramount importance.

Cauda equina neuroendocrine tumor: a report of three cases and review of the literature with focus on differential diagnosis and postoperative management.

INTRODUCTION: Cauda equina neuroendocrine tumors (CENETs), previously described as cauda equina paragangliomas (PGLs) are rare and well-vascularized benign entities which can be often misdiagnosed with other intradural tumors more common in this anatomical site, such as ependymomas and neurinomas. We describe three cases of CENETs observed at our institution with particular focus on differential diagnosis and postoperative management. Since the lack of guidelines, we performed a literature review to identify factors that can predict recurrence and influence postoperative decision making. CASE REPORT AND LITERATURE REVIEW: We report on three patients, two of them presenting with a clinical history of lower back pain and sciatica. In all cases magnetic resonance imaging (MRI) of the lumbosacral spine with and without Gd-DTPA revealed an intradural lesion with strong contrast enhancement, first described as atypical ependymoma or schwannoma. A complete tumor resection was achieved in all cases, the histopathological diagnosis classified the tumors as CENETs. In our literature review, a total of 688 articles were screened and 162 patients were included. Patients demographic data, clinical symptoms, resection and recurrence were recorded. DISCUSSION: Differential diagnosis between CENETs and other more common tumors affecting cauda equina region, such as ependymomas or schwannomas (neurinomas), is still very challenging. Due to the lack of specific clinical or radiological characteristics, a correct preoperative diagnosis is almost impossible. With this paper we want to point out that CENETs must be considered in the differential diagnosis, most of all in case of entities with atypical radiological features. According to the literature, tumor recurrence after gross total resection is unlikely, while a long-term follow-up is recommended in case of subtotal resection or local aggressive behavior.

The discrepancy in triggered electromyography responses between fatty filum and normal filum terminale.

BACKGROUND: Functional role of filum terminale (FT) was not well studied though it contains structure basis for nerve impulse conduction. We aimed to explore the possible functions of the FT from the perspective of triggered electromyography (EMG) during surgery. METHODS: We retrospectively reviewed intraoperative neurophysiological monitoring data from pediatric patients who underwent intradural surgeries at the lumbar level in Shanghai Children's. Hospital from January 2018 to March 2023. Altogether 168 cases with complete intraoperative neurophysiological recordings of the FT were selected for further analysis. Triggered EMG recordings of the filum originated from two main types of surgeries: selective dorsal rhizotomy (SDR) and fatty filum transection. RESULTS: 96 cases underwent SDR and 72 cases underwent fatty filum transection. Electrical stimulation of the FT with fatty infiltration did not elicit electromyographic activity in the monitored muscles with the maximum stimulus intensity of 4.0 mA, while the average threshold for FT with normal appearance was 0.68 mA, and 89 out of 91 FT could elicit electromyographic responses in monitored channels. The threshold ratio of filum to motor nerve roots at the same surgical segment was significantly higher in patients with fatty filum, and a cut-off point of 21.03 yielded an area under curve of 0.943, with 100% sensitivity and 85.71% specificity. CONCLUSION: Filum with normal appearance can elicit electromyographic activity in the lower limbs/anal sphincter similar to the performance of the cauda equina nerve roots. The threshold of fatty filum is different from that of normal appearing FT. Triggered EMG plays an important role in untethering surgeries.

Functional Vascular Anatomy and Arteriovenous Shunts of the Spine.

The history of vascular anatomy of the spinal cord and spine began in the late 19th century. With recent advances in endovascular and surgical treatment of vascular lesions of the spinal cord, understanding the vascular anatomy of the spinal cord has become more important than ever. Catheter angiography is the gold standard for diagnosing vascular lesions of the spinal cord, and the vascular architecture of the spinal cord itself is relatively simple, a repetition of basic longitudinal and axial structures. This review discusses the vascular anatomy of the spine and spinal cord from the embryological point of view, as well as an overview of typical spinal arteriovenous shunt diseases mainly depending on their locations: paraspinal, epidural, dural, perimedullary, intramedullary, filum terminale/cauda equina, craniocervical junction, and related diseases.

Endoscopic spinal cord untethering using a 1 cm skin incision technique in pediatrics: a technical case report.

BACKGROUND: Spinal cord untethering by sectioning the filum terminale is commonly performed in tethered cord syndrome patients with minor abnormalities such as filar lipoma, thickened filum terminale, and low conus medullaris. Our endoscopic surgical technique, using the interlaminar approach, allows for sectioning the filum terminale through a very small skin incision. To our knowledge, this procedure has not been previously reported. This is the first case report involving a 1 cm skin incision. CASE PRESENTATION: A 9-month-old male patient was referred to our neurosurgical department due to a coccygeal dimple. MRI revealed a thickened fatty filum. After considering the treatment options for this patient, the parents agreed to spinal cord untethering. A midline 1 cm skin incision was made at the L4/5 vertebral level. Untethering by sectioning the filum terminale was performed by full endoscopic surgery using the interlaminar approach. The procedure was uneventful and there were no postoperative complications. CONCLUSIONS: In terms of visibility and minimizing invasiveness, our surgical technique of using the interlaminar approach with endoscopy allows for untethering by sectioning the filum terminale through a very small skin incision.

Relationship between lumbar spinal stenosis and cauda equina movement during the Valsalva maneuver.

OBJECTIVE: To confirm the relationship between lumbar spinal stenosis (LSS) and cauda equina movement during the Valsalva maneuver. MATERIALS AND METHODS: Two radiologists at our institution independently evaluated cauda equina movement on pelvic cine MRI, which was performed for urethrorrhea after prostatectomy or pelvic prolapse in 105 patients (99 males; mean age: 69.0 [range: 50-78] years), who also underwent abdominopelvic CT within 2 years before or after the MRI. The qualitative assessment of the cine MRI involved subjective determination of the cauda equina movement type (non-movement, flutter, and inchworm-manner). The severity of LSS on abdominopelvic CT was quantified using our LSS scoring system and performed between L1/2 and L5/S1. We calculated the average LSS scores of two analysts and extracted the worst scores among all levels. RESULTS: Cauda equina movement was observed in 15 patients (14%), inchworm-manner in 10 patients, and flutter in five patients. Participants with cauda equina movement demonstrated significantly higher LSS scores than those without movement (P < 0.001, Wilcoxon's rank-sum test). A significant difference was observed in the worst LSS scores between participants without movement and those with inchworm-manner movement (P < 0.001, Bonferroni's corrected). There were no significant differences between participants without movement and those with flutter movement (P = 0.3156) and between participants with flutter movement and those with inchworm-manner movement (P = 0.4843). CONCLUSION: Cauda equina movement in cine MRI during the Valsalva maneuver is occasionally observed in patients with severe LSS, and may be associated with pathogenesis of redundant nerve roots.

Microsurgical approach for resection of the filum terminale internum in tethered cord syndrome-a case demonstration of technical nuances and vignettes.

BACKGROUND: In tethered cord syndrome due to filum terminale pathology, the surgical approach to achieve detethering of the spinal cord may vary. Traditionally, sectioning the filum through a laminectomy at the lumbosacral level is performed. METHOD: A microsurgical technique at a higher level to approach the filum below the conus tip is performed. This allows for removal of the entire distal portion of the filum through a limited interlaminar approach and dural opening. CONCLUSION: We propose a technique to transect the filum terminale below the conus tip and extract the distal filum by releasing it from its intradural attachments to minimize any remnants of the filum terminale.

Primary Malignant Lymphoma of the Cauda Equina Diagnosed after Decompression for Lumbar Spinal Stenosis: A Case Report.

Primary malignant lymphoma confinement to the cauda equina is rare. Only 14 cases of primary malignant lymphoma in the cauda equina have been reported. In these cases, the clinical features were similar to those of lumbar spinal canal stenosis (LSCS). This report describes a case of diffuse large B-cell lymphoma of the cauda equina that was diagnosed after decompression surgery for LSCS. An 80-year-old man presented with gait disturbance due to progressive muscle weakness in the lower extremities over the previous two months. He was diagnosed with LSCS, and decompression surgery was performed. However, the muscle weakness worsened after surgery; therefore, he was referred to our department. Plain magnetic resonance imaging (MRI) revealed swelling of the cauda equina. It demonstrated marked homogenous enhancement by gadolinium-diethylenetriamine pentaacetic acid. 18F-fluorodeoxyglucose positron emission tomography (18F-FDG PET) revealed diffuse accumulation of 18F-FDG in the cauda equina. These imaging findings were consistent with those of cauda equina lymphomas. To confirm the diagnosis, we performed an open biopsy of the cauda equina. Histological examination indicated diffuse large B-cell lymphoma. Considering the patient's age and activities of daily living, further treatment was not performed. The patient died four months after the first surgery. Rapid progression of muscle weakness, which cannot be prevented by decompression surgery, and swollen cauda equina on MRI may be signs of this disorder. Gadolinium-enhanced MRI, 18F-FDG PET, and histological investigation of the cauda equina should be performed for diagnosing primary malignant lymphoma of the cauda equina.

Neurological Analysis Based on the Terminal End of the Spinal Cord and the Narrowest Level of Injured Spine in Thoracolumbar Spinal Injuries.

This study aimed to clarify neurological differences among the epiconus, conus medullaris, and cauda equina syndromes. Eighty-seven patients who underwent surgery for acute thoracolumbar spinal injuries were assessed. We defined the epiconus as the region from the terminal end of the spinal cord to the proximal 1.0 to 2.25 vertebral bodies, the conus medullaris as the region proximal to < 1.0 vertebral bodies, and the cauda equina as the distal part of the nerve roots originating from the spinal cord. On the basis of the distance from the terminal end of the spinal cord to the narrowest level of the spinal canal, the narrowest levels were ordered as follows: the epiconus followed by the conus medullaris and cauda equina. The narrowest levels were the epiconus in 22 patients, conus medullaris in 37 patients, and cauda equina in 25 patients. On admission, significantly more patients had a narrowed epiconus of Frankel grades A-C than a narrowed cauda equina. At the final follow-up, there were no significant differences in neurological recovery among those with epiconus, conus medullaris, or cauda equina syndrome. Anatomically classifying the narrowest lesion is useful for clarifying the differences and similarities among these three syndromes.

Filum terminale arteriovenous shunt with nidus structure: a report of rare condition and treatment consideration.

BACKGROUND:  In the literature, filum terminale arteriovenous shunts (FTAVSs) always feature a single shunt point. Nidus-type FTAVSs have rarely been reported, and the best treatment strategy is unclear. This is a report of one exceptional case of a nidus-type FTAVS and surgical treatment of the lesion. CASE DESCRIPTION: The patient suffered from cauda equina syndrome for 9 months. Magnetic resonance imaging and spinal angiography revealed a nidus-type FTAVF at the L2 level. Surgical resection was performed in the hybrid operating room, and the nidus was completely resected with the assistance of intraoperative methylene blue angiography and neurophysiological monitoring. The postoperative neurological function was stable. CONCLUSIONS: A nidus-type arteriovenous shunt could originate from the FT, and in such cases, complete surgical resection with intraoperative neurophysiological monitoring in a hybrid operating room should be suggested.

Cauda equina syndrome after use of dural sealant in revision lumbar decompression surgery.

OBJECTIVE: We report a case of cauda equina syndrome related to the use of fibrin glue dural sealant "TISSEEL". BACKGROUND: Incidental durotomy (ID) is not uncommon in revision spinal surgery. Augmentation of the dural repair after primary closure is gaining popularity. The use of dural sealants is not risk-free. METHOD: A 65-year old man who underwent revision lumbar decompression surgery developed postoperative cauda equina syndrome. He had urinary retention, bilateral leg pain and perianal numbness on the third postoperative day. We believe this complication was related to the use of fibrin glue to manage an ID. RESULT: After the urgent surgical removal of the fibrin glue patch, the patient fully recovered with no residual neurological deficit. CONCLUSION: Cauda equina syndrome development is a potential complication after the use of fibrin glue to augment intraoperative ID. Surgeons should be aware of this potential risk so it can be managed in a timely fashion.

Surgical decompressions for cauda equina syndrome during COVID-19.

BACKGROUND: The novel coronarvirus disease (COVID-19) has had a major impact on provision of spinal neurosurgery across the world, especially in the UK, with a significant fall in operating and patient volumes, and elective clinical activities. It is unclear whether the pandemic has affected the volume of urgent spinal procedures in the UK, especially surgical decompressions for cauda equina syndrome (CES). METHODS: Therefore, we conducted a retrospective analysis of theatre records and electronic operation notes at our institution to identify all procedures performed for CES before (December 2019 to February 2020) and during (March 2020 to May 2020) the COVID-19 pandemic. Statistical analyses were performed on SPSS v22 (IBM). RESULTS: Forty-four patients underwent surgical decompressions during the study period. Over half (54.5%) were female and the median age was 45 years (range = 22-78 years). Three in four procedures were performed at L4-5 and L5-S1 levels (79.5%). There was no statistically significant difference in the number of decompressions performed each month [χ2(5)=1.818; p = 0.874]. On the other hand, the number of referrals for suspected or confirmed CES fell by 81.8% between December 2019 and April 2020. CONCLUSIONS: Our results did not show any statistically significant decline in the volume of surgical decompressions performed for CES despite the considerable fall in electronic referrals for CES and degenerative spinal conditions. This suggests that patients with critical neurological symptoms continued to present and were treated appropriately despite the restrictions imposed on spinal surgeons during the pandemic.

Cauda equina syndrome from intradural metastasis of a non-neural tumor: case report and review of literature.

BACKGROUND: Cauda equina syndrome (CES) is a challenging condition and it can be caused by variable entities. Leptomeningeal carcinomatosis (LC) is a multifocal seeding of the leptomeninges by malignant cells and it is observed in 1-8% of patients with solid tumors. Diagnosis of intradural metastases of the cauda equina is often delayed due to the non-specific characteristics of this condition but also to the delay of presentation of many patients. Cauda equina metastases usually occur in advanced cancers, but rarely can be the first presentation of disease. CASE DESCRIPTION: A 63-year-old man presented with 6 months history of low back pain and 20 d history of bilateral sciatica, hypoesthesia of the legs and the saddle, flaccid paraparesis and bowel incontinence determine by multiple nodular small lesions on the entire cauda equina with contrast-enhancement. Total-body CT showed a millimetric lesion at the lung. The patient underwent L2-L5 laminectomy and subtotal removal and histological examination showed a small cell lung carcinoma metastasis. CONCLUSIONS: In the literature, 54 cases of CES from non-CNS tumor metastasis are described. The diagnosis is challenging, back pain, with or without irradiation to the lower limbs, is the most frequently reported disturbance. In about 30% of patients there is no known malignancy and CES is the first clinical presentation. Treatment of choice is surgery, followed by radiotherapy and less frequently adjuvant chemotherapy. The surgical removal is almost always incomplete and functional outcome is often not satisfactory. Prognosis is poor.

Facet joint cyst haematoma: a rare cause of cauda equina syndrome.

Facet joint cysts are a feature of lumbar spondylosis and are an uncommon cause of radiculopathy. Facet joint cyst haematoma is a very rare entity and has previously been reported as a subacute cause of leg pain, back pain, sensory deficit and lower limb weakness. We present the unique case of facet joint cyst haematoma presenting as cauda equina syndrome. An 81 year old lady presented with a 7 day history of back pain and left foot drop, a 1 day history of perineal numbness and urinary retention with absent rectal tone, perianal anaesthesia and left leg hypoaesthesia. Emergency MRI scan demonstrated spinal canal stenosis as the aetiology of her cauda equina syndrome. She was taken to theatre for emergency lumbar decompression. At operation a facet joint haematoma compressing the cauda equina was found and extirpated with complete resolution of symptoms. In this case, the aetiology of cauda equina compression was not demonstrated effectively on pre-operative MRI scanning.

Mobile cauda equina ependymoma, case report and literature review.

The aim of this study was to describe a very rare presentation of ependymoma that can derive from intraoperative complications for surgeons and increased morbidity for the patients. Multiple cases of mobile cauda equina tumors leading to inadequate approach have been reported in the literature, however, the reports of ependymoma histology are very rare. This report describes the third adult case in recent years and a retrospective review of cases reported in the literature until today. We show the clinical and radiographic presentation of a 79 years old patient that presented a mobile cauda equina tumor in the preoperative image, who went to surgery for resection and arthrodesis, obtaining in post-operative histology the diagnostic of ependymoma. The preoperative image shows the migration of the tumor avoiding the wrong approach. The patient went to surgery for laminectomy, pedicular screw arthrodesis L1-S1, and tumor removal, obtaining a complete resection and confirmed histology diagnostic of ependymoma, unfortunately, the patient died five days after by a cardiac arrest. The recent literature reports only four cases of mobile ependymoma, two of them in pediatrics patients and just only two adult cases, which means this is the third adult case of an ependymoma. Mobile cauda equina ependymoma is a very rare neoplasm presentation but is an entity that can lead to mistakes in the approach and may be useful for the neurosurgeons who day per day treat this pathology beware of this possibility.

Paraganglioma of the cauda equina: a tertiary centre experience and scoping review of the current literature.

Cauda equina paragangliomas are rare benign extra-adrenal neuroendocrine tumours arising from the neural crest cells associated with autonomic ganglia. These tumours are often mistaken preoperatively for ependymomas or schwannomas. Patients present with axial or radicular pain with or without neurological deficits. Recurrence, secretory features and length of follow-up are controversial. We conducted a retrospective cohort study of paraganglioma through searching a prospectively maintained histopathology database. Patient demographics, presentation, surgery, complications, recurrence, follow-up and outcome between 2004 and 2016 were studied. The primary aim was to collate and describe the current evidence base for recurrence and secretory features of the tumour. The secondary objective was to report outcome and follow-up strategy. A scoping review was performed in accordance with the PRISMA-ScR Checklist. Ten patients were diagnosed (M:F 7:3) with a mean age of 53.6 ± 5.1 (range 34-71 years). MRI scans revealed intradural lumbar enhancing lesions. All patients had complete microsurgical excisions without adjuvant therapy with no recurrence with a mean follow-up of 5.1 ± 1.4 years. Tumours were attached to the filum terminale. Electron microscopic images demonstrated abundant neurosecretory granules with no evidence of catecholamine production. A total of 620 articles were screened and 65 papers (including ours) combining 121 patients (mean age 48.8 and M:F 71:50) were included. The mean follow-up was 3.48 ± 0.46 (range 0.15-23 years). Back pain was the most common symptom (94%). Cure following surgery was achieved in 93% of the patients whilst 7% had recurrence. Total resection likely results in cure without the need for adjuvant therapy or prolonged follow-up. However, in certain situations, the length of follow-up should be determined by the treating surgeon.

Outcomes of cauda equina syndrome due to lumbar disc herniation after surgical management and the factors affecting it: a systematic review and meta-analysis of 22 studies with 852 cases.

PURPOSE: This study aimed to investigate the long-term clinical outcomes after surgical decompression in cauda equina syndrome (CES) and see if any preoperative patient-related factors contributed to this outcome. METHODS: A systematic literature search was conducted in the electronic databases of PubMed, Embase, Scopus, and Ovid. Data regarding outcome parameters from eligible studies were extracted. Meta-analysis was performed using a random-effect model. RESULTS: A total of 852 patients (492 males and 360 females), with a mean age of 44.6 ± 5.5 years from 22 studies diagnosed with cauda equina syndrome and undergoing surgical decompression, were included in the meta-analysis; however, not all studies reported every outcome. The mean follow-up period was 39.2 months, with a minimum follow-up of 12 months in all included studies. Meta-analysis showed that on long-term follow-up, 43.3% [29.1, 57.5] (n=708) of patients had persistent bladder dysfunction. Persistent bowel dysfunction was observed in 31.1% [14.7, 47.6] (n=439) cases, sensory deficit in 53.3% [37.1, 69.6] (n=519), motor weakness in 38.4% [22.4, 54.4] (n=490), and sexual dysfunction in 40.1% [28.0, 52.1] (n=411). Decompression within 48 hours of the onset of symptoms was associated with a favourable outcome in terms of bladder function with 24.6% [1.6, 50.9] (n=75) patients having persistent dysfunction, whereas 50.3% [10.3, 90.4] (n=185) of patients in studies with a mean time to decompression after 48 hours had persistent bladder dysfunction. Other factors such as speed of onset and sex of the patients were not found to significantly impact long-term bladder outcomes. CONCLUSION: The long-term outcomes of CES after decompression are enumerated. Decompression within 48 hours of the onset of symptoms appears to result in fewer patients with persistent bladder dysfunction. However, a randomized controlled trial is required to conclusively determine whether early decompression leads to better outcomes.

Arteriovenous malformations of the filum terminale: clinical characteristics, angioarchitecture, and management of a rare spinal vascular pathology.

OBJECTIVE: The goal of this study was to describe clinical and neuroradiological features of arteriovenous malformations of the filum terminale (FT AVMs) and to present the authors' diagnostic and therapeutic management in this rare disease. METHODS: The presented cases were retrieved from a retrospectively collected database of all spinal vascular malformations treated between June 1992 and December 2021 at the Rheinisch-Westfälische Technische Hochschule (RWTH) University Hospital Aachen. Pretreatment and follow-up clinical and neuroradiological data were analyzed for this study. RESULTS: Data in 15 patients with FT AVM with a mean age of 60 years were included, with an overall incidence of FT AVM of 19% among all spinal AVMs in our cohort. Twelve of 15 (80%) patients were men. Nonspecific but typical clinical and MR findings of thoracolumbar congestive myelopathy were found in all patients. Spinal MR angiography, performed in 10 patients, identified in all cases the arterialized FT vein as well as a lumbar/lumbosacral location of an AV shunt. Digital subtraction angiography (DSA) showed an arterial supply solely via the FT artery in 12/15 (80%) patients and via an additional feeder from the lumbosacral region in the other 3/15 (20%) patients. All patients were treated surgically. During 1-year follow-up, 2 patients presented with recurrent FT AVM due to further arterial supply from the lumbosacral region, and were treated surgically. Neurological status was improved in all patients within the 1-year follow-up, with marginal further changes during long-term follow-up. CONCLUSIONS: Congestive myelopathy is the major pathological mechanism of symptoms in these patients, with no evidence for intradural bleeding. Missing the presence of possible multiple arterial supply of FT AVM during DSA may result in misdiagnosis and/or insufficient treatment. Due to the frequently prolonged course of FT artery, resection of the FT AVM may be a favorable treatment modality in comparison with endovascular treatment. Follow-up examinations are obligatory within the first 3 years after treatment, and further MR angiography and DSA examinations are indicated if congestive myelopathy persists.

Lumbar nerve root biopsy with fascicle dissection and functional mapping: how I do it.

BACKGROUND: Lumbosacral plexopathies with unclear etiology are a rare entity. In certain cases, if workup unrevealing and medical management is suboptimal, an open lumbar nerve root biopsy may be considered. METHOD: A standard lumbar laminectomy is performed for access to the intradural contents. The dura is opened at midline in a standard fashion. Single nerve roots are selected and stimulated for an EMG response. A nerve fascicle is then dissected and stimulated before excision. CONCLUSION: Lumbar nerve root biopsy is feasible and safe. All non-invasive workup needs to be completed and negative before performing this procedure.

Minimal invasive interlaminar approach for untethering of fatty filum terminale in pediatric patients - how I do it.

BACKGROUND: Fatty filum terminale is a form of spinal dysraphism and a third of all patients develop symptoms such as sensory, motor, and urinary impairment. Early surgery at 6 months has the advantage that the bone density is still soft, and the patients are not ambulatory yet, promoting faster healing. METHOD: We present our minimal invasive surgical technique for FFT untethering. CONCLUSION: Due to the low complication rate and the potentially high benefit of surgery, prophylactic untethering is recommended.