Teflon granulomas mimicking cerebellopontine angle tumors following microvascular decompression

Microvascular decompression using autologous muscle graft for trigeminal neuralgia: a case series and meta-analysis

PURPOSE

We aimed to describe a case series of patients diagnosed with trigeminal neuralgia (TN) who were submitted to microvascular decompression (MVD) using autologous muscle graft (AMG) and perform a systematic review and meta-analysis.

METHODS

Forty-four adult patients who underwent MVD using AMG between 2012 and 2022 were studied retrospectively. Demographic, clinical, and surgical factors were assessed. We systematically reviewed PubMed, Embase, and Cochrane Library from inception to May 2023. We used random-effects model for all outcomes. Heterogeneity was assessed with I2. We used R software 4.3.1 for all statistical analyses.

RESULTS

Among patients in the case series, the mean age was 52 ± 12.9 years, and the proportion of females was 65.9%. Forty-one patients (93.2%) presented complete pain relief after a mean follow-up of 7.7 years. The pooled analysis of immediate pain relief was 91.3% (95% CI 82-96%; I2=78%). The good pain relief during follow-up was 88.2% (95% CI 78-94%; I2=80%) at follow-up. The recurrence rates at 6, 12, 36 months, and during follow-up were 6.2%, 10.5%, 10.3%, and 11%, respectively.

CONCLUSION

In this case series and meta-analysis of over 440 patients, our findings suggest that the practice of MVD using AMG may be an efficient option in the short term as surgical treatment for TN. Further trials should compare AMG with other materials and its effectiveness in a long-term follow-up.

Sling technique in microvascular decompression surgery for trigeminal neuralgia: early experience and functional outcomes

Background

Trigeminal neuralgia (TGN) is a facial pain disorder often caused by arterial compression of the trigeminal nerve. Microvascular decompression (MVD) remains the most definitive treatment for this disorder, with a reported cure rate between 60 and 80%. MVD techniques often involve a retrosigmoid craniotomy with placement of an inert foreign material, such as Gore-Tex or Teflon, between the nerve and the compressing vessel.

Recurrence of TGN after MVD has been associated with vessel migration and adhesion formation. In this study, we tested the use of Gore-Tex sling, fixed in place with fibrin glue to displace the compressing vessel away from the nerve.

Results

This is a retrospective study including 20 patients who had an MVD for treatment of idiopathic TGN where a sling of Gore-Tex was used with the application of fibrin glue to prevent dislocation of the vessel. It showed that sling MVD technique is an effective method for treatment of classic trigeminal neuralgia. Eighteen patients improved within 2 weeks postoperatively. One patient had recurrence of symptoms and was reoperated 1 year later.

Conclusion

Gore-Tex slinging technique is a safe simple technique for preventing re-dislocation of the offending vessel and thus recurrence of symptoms. However, larger series is needed to judge on the long-term efficacy and safety of this technique.

Microelectrode implants, inflammatory response and long-lasting effects on NADPH diaphorase neurons in the rat frontal cortex

At present, one of the main therapeutic challenges comprises the development of technologies to improve the life quality of people suffering from different types of body paralysis, through the reestablishment of sensory and motor functions. In this regard, brain-machine interfaces (BMI) offer hope to effectively mitigate body paralysis through the control of paralyzed body parts by brain activity. Invasive BMI use chronic multielectrode implants to record neural activity directly from the brain tissue. While such invasive devices provide the highest amount of usable neural activity for BMI control, they also involve direct damage to the nervous tissue. In the cerebral cortex, high levels of the enzyme NADPH diaphorase (NADPH-d) characterize a particular class of interneurons that regulates neuronal excitability and blood supply. To gain insight into the biocompatibility of invasive BMI, we assessed the impact of chronic implanted tungsten multielectrode bundles on the distribution and morphology of NADPH-d-reactive neurons in the rat frontal cortex. NADPH-d neuronal labeling was correlated with glial response markers and with indices of healthy neuronal activity measured by electrophysiological recordings performed up to 3 months after multielectrode implantation. Chronic electrode arrays caused a small and quite localized structural disturbance on the implanted site, with neuronal loss and glial activation circumscribed to the site of implant. Electrodes remained viable during the entire period of implantation. Moreover, neither the distribution nor the morphology of NADPH-d neurons was altered. Overall, our findings provide additional evidence that tungsten multielectrodes can be employed as a viable element for long-lasting therapeutic BMI applications.

Case report: Teflon granuloma following microvascular decompression manifesting as light-triggered trigeminal neuralgia

Trigeminal Neuralgia is commonly triggered by stimuli in the area of the trigeminal nerve innervation. We report an exceptionally rare case of a 61-year-old woman who complained of recurrent trigeminal neuralgia, which sole trigger was seeing a bright light. Teflon felt that was placed on the nerve root in the initial surgery was suspected of causing this rare type of trigeminal neuralgia. A reflex circuit linking luminance to trigeminal nerve activity may be implicated in activating a trigeminal nociceptive pathway by a bright light trigger.

Two cases of asymptomatic Teflon granulomas following microvascular decompression mimicking cerebellopontine angle tumours: lessons learnt in the neuro-oncology multidisciplinary team

We present the cases of two patients with asymptomatic Teflon granulomas which were incidentally found years after microvascular decompression and presented to the neuro-oncology multidisciplinary team as possible cerebellopontine angle tumours. Teflon granulomas can be asymptomatic and they can radiologically resemble cerebellopontine angle tumours. It is important that all relevant information is available to the neuro-oncology multidisciplinary team for adequate assessment and appropriate treatment recommendations.

A New Application of Gelatin Sponge in the Treatment of Hemifacial Spasm by Microvascular Decompression: A Technical Note

OBJECTIVES

 Microvascular decompression (MVD) for facial nerve remains the highly efficient hemifacial spasm (HFS) treatment. Nonetheless, a variety of cases have poor response to MVD. Using Teflon plus gelatin sponge in MVD seems to be a good solution. No existing study has examined the efficacy of using Teflon combined with gelatin sponge during MVD for HFS. Therefore, this study aimed to compare the efficacy of Teflon combined with gelatin sponge in HFS patients relative to that of Teflon alone.

PATIENTS AND METHODS

 We retrospectively compared the follow-up results of patients treated with Teflon and gelatin sponge with those treated with Teflon alone previously. Six hundred and eighty-eight primary HFS patients undergoing surgery from January 2010 to January 2018 were retrospectively analyzed. Three hundred and forty-seven cases received simple Teflon, while 342 cases underwent Teflon combined with gelatin sponge.

RESULTS

 In the Teflon plus gelatin sponge group, the incidences of facial palsy and hearing loss at 1 day, 1 year, and 2 years following surgery was significantly lower than those in the simple Teflon group. Differences in the success rates between Teflon plus gelatin sponge and the simple Teflon group were not statistically significant at 1 day, 1 year, and 2 years after surgery. The recurrence rate in the Teflon plus gelatin sponge group was significantly lower at 2 years.

CONCLUSION

 For HFS patients undergoing MVD, using Teflon plus gelatin sponge can remarkably reduce the incidence of recurrence, facial palsy, and hearing loss compared with those using Teflon alone.

Facial root entry/exit zone contact in microvascular decompression for hemifacial spasm: a historical control study

Background

Microvascular decompression (MVD) surgery is recognized as an effective treatment for hemifacial spasm (HFS). In MVD surgery, biocompatible materials are usually implanted in situ at the neurovascular conflict site in contact with the offending vessel and the facial root entry/exit zone (REZ). Another procedure of implanting the materials between the responsible vessel and the supraolivary fossa without REZ contact has also been applied. However, it is unclear whether there are any differences between these 2 procedures (REZ-contact procedure vs. REZ-non-contact procedure). Therefore, the aim of the present study was to investigate the effect of the placement of implants (contacting or not contacting the facial REZ) on surgical operations and outcomes

Methods

A historical control study was performed. Clinical data of HFS patients who underwent MVD between December 2016 and November 2018 were reviewed and categorized into 1 group with the REZ-contact procedure or another group with the REZ-non-contact procedure according to the decompression strategy they received. Clinical demographics, postoperative outcomes, and complications were collected and compared between the two groups.

Results

Not all patients are suitable for REZ-non-contact decompression. A total of 205 patients were enrolled: 112 in the REZ-contact group and 93 in the REZ-non-contact group. In the early postoperative period, the complete cure rate in the REZ-non-contact group was significantly higher than that in the REZ-contact group. The reappearance and partial relief rates in the REZ-contact group were significantly higher than those in the REZ-non-contact group. The incidence of short-term neurological complications, especially hearing loss and transient facial palsy, was lower in the REZ-non-contact group (P=0.043). But for long-term follow-up of >1 year, there was no significant difference between the two groups in either curative effects or neurological complications. The operating time for REZ-non-contact decompression was relatively longer than for REZ-contact decompression (P=0.000). An unexpected subdural hemorrhage occurred in the REZ-non-contact group.

Conclusions

REZ-non-contact decompression procedure showed superiority only in short-term postoperative outcomes. Given its limitations and potential risks, the REZ-non-contact procedure can be used as an alternative individualized strategy in MVD, and there is no need to pursue REZ-non-contact during the decompression.

Case report of recurrent hemifacial spasm attributed to over-impaction with Teflon sponge

Background:

Hemifacial spasm (HS) is a muscular disorder frequently exacerbated by arterial compression amenable to surgical intervention through microvascular decompression (MVD). Recurrence is a known cause and warrants investigation.

Case Description:

A 65-year-old woman presented with the left HS of 7 years duration. Her symptoms were initially well controlled with botulinum toxin injections. However, these injections eventually lost their effectiveness, necessitating MVD. At surgery, the anterior inferior cerebellar artery was indenting the facial nerve at its root entry zone. This was carefully dissected away, and several Teflon (polytetrafluoroethylene) felt pledgets were used for decompression. Postoperatively, the patient reported great improvement of her symptoms for 3 months. Gradually her spasms returned, intermittently at first, until finally they became persistent 6 months postoperatively. An MRI was obtained showing elevation and posterior displacement of the VII-VIII complex by the pledgets. After failing to improve, the patient opted for reoperation 10 months after initial MVD. At surgery, the Teflon pledgets were displacing the VII-III nerves posteriorly and superiorly. The Teflon pledgets were dissected free, and the nerve dis-impacted. On her postoperative visit 1 year later, she is spasm free, subjectively, and objectively.

Conclusion:

This case illustrates the value of re-imaging recurrent HS, and re-exploration with a favorable rkesult.

Intruding implements: a pictorial review of retained surgical foreign objects in neuroradiology

Intra-cranial and spinal foreign body reactions represent potential complications of medical procedures. Their diagnosis may be challenging as they frequently show an insidious clinical presentation and can mimic other life-threatening conditions. Their pathophysiological mechanism is represented by a local inflammatory response due to retained or migrated surgical elements. Cranial interventions may be responsible for the presence of retained foreign objects represented by surgical materials (such as sponges, bone wax, and Teflon). Spinal diagnostic and therapeutic procedures, including myelography, chordotomy, vertebroplasty, and device implantation, are another potential source of foreign bodies. These reactions can also follow material migration or embolization, for example in the case of Lipiodol, Teflon, and cement vertebroplasty. Imaging exams, especially CT and MRI, have a central role in the differential diagnosis of these conditions together with patient history. Neuroradiological findings are dependent on the type of material that has been left in or migrated from the surgical area. Knowledge of these entities is relevant for clinical practice as the correct identification of foreign bodies and related inflammatory reactions, material embolisms, or migrations can be difficult. This pictorial review reports neuroradiological semeiotics and differential diagnosis of foreign body-related imaging abnormalities in the brain and spine.

Surgical Interventions for Cervical Radiculopathy Caused by a Vertebral Artery Loop: A Case Report and Review of the Literature

BACKGROUND

Aberrant vertebral artery loops are a rare clinical condition, with sparse data regarding the optimal treatment guidelines for individual patients. The heterogeneity of treatment options in the literature creates a problem when tailoring treatments to individual patients. In this review of the literature, multiple surgical treatments for cervical vertebral artery loops were analyzed and compared. In addition, this article provides a clinical case of a patient with a vertebral artery loop.

METHODS

A literature review was conducted to identify studies investigating surgical treatments for a vertebral artery loop. Different surgical techniques were examined and the involved techniques and approaches described. The outcomes were assessed for each study and the effectiveness of the treatment determined.

RESULTS

Twelve articles met the inclusion criteria for this review. Six types of surgical interventions were found in the literature. Each intervention had similar postoperative results, leading to either a significant improvement or a complete resolution of symptoms.

CONCLUSIONS

Multiple successful surgical interventions have been described in the medical literature. However, because of the lack of evidence-based studies, no surgical intervention protocol could be determined. Treatment should therefore be tailored to individual patients' characteristics. Because not every radiologically detected vertebral artery loop is the main reason for a patient's symptoms, a thorough multidisciplinary approach is justified and advocated in patients with an atypical presentation, before a neurosurgical intervention takes place. More deliberate clinical decisions can be made once the understanding of the pathogenesis of this rare disease entity has been established and treatment protocols formulated.

Polytetrafluoroethylene granuloma-associated facial palsy following microvascular decompression

OBJECTIVE

Microvascular decompression (MVD) may be employed in the management of hemifacial spasm (HFS), wherein a pledget of polytetrafluoroethylene (i.e., Teflon, Chemours, Wilmington DE) is sometimes introduced to separate an offending vessel from the cisternal segment of facial nerve. Rarely, Teflon may cause a granulomatous reaction resulting in nerve palsy. We here present the first case series of facial palsy thought to be secondary to Teflon granuloma following MVD for HFS.

METHODS

A data repository of 1,312 patients with facial palsy was reviewed to identify individuals who had previously undergone MVD for HFS. Data collected include age at time of MVD, age at onset of facial weakness and at presentation, House-Brackmann scores, clinician-graded facial function using the Electronic Facial Paralysis Assessment scale, imaging findings, and therapeutic interventions and outcomes.

RESULTS

Six patients meeting criteria were identified. Average time between MVD with Teflon placement and onset of facial weakness was 16.1 (±4.9) years (range 9.3-23.3 years). Initial House-Brackmann scores were as follows: four patients with V/VI and one each with III/VI and IV/VI. Interventions included eyelid weight placement (n = 3), chemodenervation (n = 2), static suspension with tensor fascia latae (n = 2), dynamic reanimation with cranial nerves V to VII transfer (n = 1), and temporalis muscle transfer (n = 1).

CONCLUSION

Teflon granuloma should be considered in the differential diagnosis for patients presenting with new onset facial weakness with a previous history of MVD for HFS. It remains unknown whether early granuloma extirpation is effective. Prompt diagnosis allows consideration of time-sensitive nerve transfer procedures to reanimate facial function.

LEVEL OF EVIDENCE

4 Laryngoscope, 130:1422-1427, 2020.

Surgical Outcomes of Revision Microvascular Decompression for Persistent or Recurrent Hemifacial Spasm After Surgery: Analysis of Radiologic and Intraoperative Findings

OBJECTIVES

Microvascular decompression (MVD) is the treatment of choice for hemifacial spasm (HFS), due to the high rate of complete resolution associated with MVD. However, some patients experience recurrent or persistent symptoms after surgery. In this study, we evaluated the causes of recurrence or failure based on our surgical experience with revision of MVD for HFS and analyzed the relationship between surgical outcomes and radiologic and intraoperative findings.

METHODS

Among more than 2500 patients who underwent MVD surgery for HFS, 23 patients received a second MVD in our hospital from January 2002 to December 2017. Three-dimensional time-of-flight magnetic resonance angiography and reconstructed imaging were used to identify the culprit vessel and its conflict on the root exit zone (REZ) of the facial nerve. We reviewed patients' medical records and operation videos to identify the missing points of first surgery.

RESULTS

In our experience with revision of MVD, 8 patients had incomplete decompression, such as single-vessel decompression of multiple offending vessels. Teflon was not detected at the REZ but was found in other locations in 12 patients. Three patients had severe adhesion with previous Teflon around the REZ. Nineteen patients had excellent surgical outcomes at immediate postoperative evaluation; 20 patients showed spasm disappearance at 1 year after surgery and 3 patients showed persistent symptoms. Neurovascular contacts around the REZ of the facial nerve were revealed on magnetic resonance imaging of incomplete decompression and Teflon malposition patient groups. There were no clear neurovascular contacts in the patients with severe Teflon adhesion.

CONCLUSIONS

The decision regarding secondary MVD for persistent or recurrent spasm is troubling. However, if neurovascular contact was observed in the MRI of the patient and there were offending vessels, the surgical outcome might be favorable.

Surgical Techniques and Long-Term Outcomes of Flexible Neuroendoscopic Aqueductoplasty and Stenting in Infants with Obstructive Hydrocephalus: A Single-Center Study

OBJECTIVE

To technically review and explore long-term follow-up results of aqueductoplasty and stenting under flexible neuroendoscopy in infantile obstructive hydrocephalus.

METHODS

The clinical data, surgical techniques, and long-term effects in 14 infants with obstructive hydrocephalus treated by flexible neuroendoscopic aqueductoplasty and stenting between 2008 and 2010 were analyzed retrospectively.

RESULTS

The 14 infants had a mean age of 5.71 ± 3.10 months (range, 2-11 months) and a mean duration of follow-up of 62.64 ± 34.52 months (range, 9-121 months). Subdural effusion was observed in 4 infants (28.6%) after surgery. There were no deaths or serious complications related to intracranial stent placement. Three infants (21.4%) failed, 2 due to proximal aqueduct occlusion from a short stent length and 1 due to intraluminal ependymal adhesion obstruction. One case was abandoned when a second surgical adjustment stent was unsuccessful, and the other 2 cases went to shunt surgery.

CONCLUSIONS

Aqueductoplasty with stenting is a feasible and safe surgical procedure for treating infants with midbrain aqueduct stenosis or occlusion. However, the optimal stent material and definitive outcomes after this procedure require additional long-term follow-up studies in large numbers of infants.

Foreign Body Granuloma After Cranial Surgery: A Systematic Review of Reported Cases

BACKGROUND

In cranial surgery, different foreign body (FB) materials are used and may be left intentionally or unintentionally in the surgical field after closure, inducing a foreign body granuloma (FBG). This is a rare complication in neurosurgery, but it may be a diagnostic dilemma, with sometimes medicolegal implications.

METHODS

We performed a systematic review of the English literature between 1965 and 2018 and found a total of 77 articles concerning 100 cases of FBG caused by retained material located within the cranium or surrounding soft tissues.

RESULTS

There were 60 females and 40 males, with ages ranging from 1 to 77 years. Most initial diagnoses were cranial/intracranial tumors, trigeminal neuralgia, hemifacial spasm, intracranial aneurysm, hydrocephalus, head injury, infectious disease, and nontraumatic intracerebral hematoma. The interval from the causative surgical operation to presentation of the FBG ranged from 2 weeks to 20 years. Various radiologic modalities were used and histologic study confirmed the presence of FBG in all patients. Intentional FB was used and left in 77 patients, and unintentional FB was found postoperatively in 23 patients. Associated infection was found in 13 patients. Complete recovery was seen in 47.6% of patients with sufficient data.

CONCLUSIONS

Despite being unusual, a retained FBG should be considered in the differential diagnosis of any patient after cranial surgery. A history of surgery, clinical symptoms, physical examination findings, laboratory results, and the use of appropriate neuroimaging explorations may provide a correct preoperative diagnosis. In addition, unintentionally retained FBs are preventable errors in the operating room.

Diagnostic challenges in meningioma

Advances in molecular profiling and the application of advanced imaging techniques are currently refreshing diagnostic considerations in meningioma patients. Not only technical refinements but also sophisticated histopathological and molecular studies have the potential to overcome some of the challenges during meningioma management. Exact tumor delineation, assessment of tumor growth, and pathophysiological parameters were recently addressed by "advanced" MRI and PET. In the field of neuropathology, high-throughput sequencing and DNA methylation analysis of meningioma tissue has greatly advanced the knowledge of molecular aberrations in meningioma patients. These techniques allow for more reliable prediction of the biological behavior and clinical course of meningiomas and subsequently have the potential to guide individualized meningioma therapy. However, higher costs and longer duration of full molecular work-up compared with histological assessment may delay the implementation into clinical routine.This review highlights the diagnostic challenges of meningiomas from both the neuroimaging as well as the neuropathological side and presents the latest scientific achievements and studies potentially helping in overcoming these challenges. It complements the recently proposed European Association of Neuro-Oncology guidelines on treatment and diagnosis of meningiomas by integrating data on nonstandard imaging and molecular assessments most likely impacting the future.

The diagnosis and management of a vertebral artery loop causing cervical radiculopathy

BACKGROUND

Cervical radiculopathies are rarely caused by vertebral artery loop formation, which is estimated to be present in less than 3% of patients. It is uncertain what causes the loop formation: some propose an association with spondylotic changes or trauma, whilst others suggest hypertension and atherosclerosis may be responsible. CASE REPORT 1: A 35-year-old male patient presented with signs and symptoms of cervical radiculopathy that was not improved with anterior cervical discectomy and fusion surgery performed 2 years beforehand. Vertebral artery loop was discovered at the level C5/6 on the MRI. Vertebral artery transposition surgery via a lateral approach was performed at the level of the left C5/6 for symptoms of left C6 radiculopathy. Deroofing of the transverse process was performed with post-surgical complete improvement in weakness and pain. CASE REPORT 2: A 48-year-old female patient presented with a 10-year history of left shoulder pain with occasional radiation into her middle three fingers accompanied by intermittent paraesthesia and weakness. Numerous shoulder surgeries, Botox injections and suprascapular nerve blocks had not provided any significant benefit. A vertebral artery loop was identified at the level of C3/4 and C4/5 on the left with cervical MRI. Transposition surgery of these two levels provided some post-surgical improvement in pain.

CONCLUSION

Vertebral artery loop formations are a rare but potential cause for cervical radiculopathy. In two cases, the loop formations were not radiographically reported on MRI, thus clinicians should be aware of this as a differential diagnosis in the management of cervical radiculopathy. The presented surgical approach may be useful in managing future cases of vertebral artery loop formation causing cervical radiculopathy resistant to conservative measures.