Neuroma Group Research Articles

Clinical Characteristics and Corticosteroid Responses of Acoustic Neuroma Treated as Idiopathic Sudden Sensorineural Hearing Loss.

Few investigations have been conducted on the clinical characteristics of the differential diagnosis of acoustic neuroma with acute sensorineural hearing loss and idiopathic sudden sensorineural hearing loss. The aim of the study was to investigate the clinical characteristics of the differential diagnoses between acoustic neuroma and idiopathic sudden sensorineural hearing loss. The medical records of patients with acute sensorineural hearing loss (142 ears), including acoustic neuroma (19 ears) and idiopathic sudden sensorineural hearing loss (123 ears), who underwent audiometric and hematologic examinations and received systemic corticosteroid treatment, were retrospectively reviewed. Hematological examination revealed that the erythrocyte sedimentation rate and fibrinogen values were significantly higher in the idiopathic sudden sensorineural hearing loss group compared to the acoustic neuroma group. Although all patients received corticosteroid treatment, hearing thresholds at the initial examination and 3 months after corticosteroid treatment were significantly higher in the idiopathic sudden sensorineural hearing loss group compared to the acoustic neuroma group at all frequencies. However, hearing recovery was worse in the acoustic neuroma group compared to the idiopathic sudden sensorineural hearing loss group. Furthermore, speech discrimination and short increment sensitivity index tests were not significantly different between the acoustic neuroma and idiopathic sudden sensorineural hearing loss groups. This is the first study to reveal that speech discrimination and short increment sensitivity index tests are not useful for the differential diagnoses between acoustic neuroma and idiopathic sudden sensorineural hearing loss, whereas erythrocyte sedimentation rate and fibrinogen, blood biomarkers of inflammation and blood viscosity, would be considered valuable. Furthermore, acoustic neuroma should be considered in cases where acute sensorineural hearing loss did not recover after corticosteroid treatment, although the initial hearing loss was mild.

Improving Nerve Coaptation Outcomes in Targeted Muscle Reinnervation: A Novel Bioengineered Device

PURPOSE: Despite extensive research efforts, neuroma formation remains a persistent challenge in the treatment of peripheral nerve injuries. Targeted muscle reinnervation (TMR) has emerged as a promising approach for prevention and treatment of painful neuromas. However, the significant size-mismatch inherent to TMR contributes to substantial axonal escape from the coaptation site and consequently patients rarely achieve full resolution of symptoms. To address this limitation, we developed a funnel shaped conduit to mechanically guide the regenerating axons across the repair site and thereby prevent axonal escape. The conduit is modified from a biodegradable nerve wrap that has demonstrated excellent biocompatibility and anti-inflammatory properties in prior studies by our group. Given the limited capacity of the distal nerve stump to accept the axons regenerating from the larger proximal nerve, we incorporated chondroitin sulfate proteoglycans (CSPGs) within the lumen of the conduits to inhibit the majority of the regenerating axons. We applied the funnel conduit with and without CSPGs in a TMR model to assess the impact on functional recovery and neuroma formation at the repair site. METHODS: A conduit device composed of nonwoven poly-ε-caprolactone (PCL) was developed by electrospinning. The conduit walls prevent intraneural macrophage infiltration and inflammation, which limits scarring and fibrosis at the coaptation site. Within the conduit, CSPGs incorporated into a nanofiber hydrogel form an interpenetrating network. Using a TMR rodent hindlimb model, we tested the effects of this device on neuroma formation, axonal growth, muscle reinnervation, pain behaviors, and functional recovery. RESULTS: Qualitative assessment of the coaptation site showed that the significant size mismatch between the sciatic nerve and tibial branch resulted in neuroma formation in the TMR and neuroma groups, while the use of the conduit resulted in tapered reinnervation of the sciatic nerve, demonstrating the effectiveness of this device in mechanically guiding axonal growth. Neuroma and TMR groups demonstrated more co-labelling of Substance P and SCG10 (regeneration marker) than conduit groups. No significant differences were observed between the Positive Control and CSPG-Conduit groups in gastrocnemius muscle mass, myofibril cross-sectional area, and neuromuscular junction reinnervation. However, the Positive Control group exhibited significantly greater gastrocnemius mass than the TMR and the Negative Control groups, suggesting better axonal guidance and muscle reinnervation was enabled by the conduit. By Week 5, mechanical stimulation of the coaptation site elicited significantly less pain behavior response scores in the CSPG-Conduit group compared with the Neuroma group. Autotomy scores of CSPG-Conduit scores were similar to Positive Control scores, suggesting successful prevention of neuroma formation. CONCLUSIONS: We introduce a novel engineered device in which mechanical guidance of axons is combined with inhibition of axonal regeneration to prevent neuroma formation. This conduit presents a biologically compatible, noninvasive means by which we could optimize postoperative care of peripheral nerve injury. Built from materials and components currently used in FDA-approved devices, the device is poised for clinical translation. This therapeutic approach has high potential for success as a reliable technique to prevent neuromas and facilitate prosthetic use.

The ability of gap detection in patients with acoustic neuroma

Objective:We aimed to provide a basis for the clinical study of acoustic neuroma through investigating the ability of temporal gap detection in acoustic neuroma patients and comparing the abilities with those in people with normal and impaired hearing. Method:Twenty-two patients with confirmed acoustic neuroma, 30 normal hearing patients and 16 patients with sensorineural hearing loss were enrolled in this study, and the interval threshold for awareness of each group was tested. Result:The mean temporal gap detection test（TGDT） threshold of the normal hearing group was （3.56±0.82） ms; the sensorineural hearing loss group's was （3.91±1.46） ms; TGDT threshold of healthy side of acoustic neuroma patients was （4.01±1.86） ms; TGDT threshold of the impaired side of acoustic neuroma patients was （9.48±9.46）ms. After statistical analysis, we found that excepting for the test of phonetically balanced maximum （PBmax） and TGDT, other results in the sensorineural hearing loss group and normal hearing group is of no statistical difference. The difference between the affected side of the acoustic neuroma group and the other groups was statistically significant （P<0.05）. There was no linear correlation between the value of TGDT threshold and PBmax （P> 0.05）. TGDT value of normal people has no significant difference among people of different genders and ears of different individuals. Conclusion:The TGDT of the healthy ear of the patients with acoustic neuroma is not affected, and there is no significant change compared with normal people. The TGDT test has a good consistency with the PBmax results. The time interval response ability of the affected ear of the acoustic neuroma is significantly weaker than that of the normal person. The combined test of PBmax and TGDT will contribute to the diagnosis of retrocochlear disease.

Post-surgical neuromas in patients with total alloplastic temporomandibular joint reconstruction: a retrospective case series

This study evaluated pain scores and maximal incisal opening (MIO) in patients with total alloplastic temporomandibular joints found to have post-surgical neuromas following revision arthroplasty, compared with patients who underwent revision arthroplasty without neuromas. 19 cases were reviewed of which 11 had neuromas excised. Data were available for 8 cases in the immediate postoperative period and 7 cases had follow-up data. 8 patients had revision arthroplasty with excision of scar tissue (7 with postoperative, 4 with long-term data). Follow-up ranged from 2 months to 5.9 years (mean 1.2 years). 6 of 8 patients obtained clinically significant pain reduction in the immediate postoperative period when their neuromas were excised, compared with 3 of 7 patients without neuromas. On long-term follow-up, 3 of 7 patients in the neuroma group had clinically significant pain reduction, 3 reported lower pain scores, 1 had no pain change. No patients had increased pain. 1 of 4 patients in the scar revision group had clinically significant pain reduction, 2 had no change, 1 reported increased pain. Mean MIO was 23 mm preoperative and 28 mm postoperative in patients with neuromas, compared with 27.75 mm and 31.25 mm, respectively, in patients without neuromas.

Schwann Cell Engraftment Into Injured Peripheral Nerve Prevents Changes in Action Potential Properties

Peripheral nerve injury results in changes in action potential waveform, ion channel organization, and firing properties of primary afferent neurons. It has been suggested that these changes are the result of reduction in basal trophic support from skin targets. Subcutaneous injections of Fluro-Gold (FG) in the hind limb of the rat were used to identify cutaneous primary afferent neurons. Five days after FG injection, sciatic nerves were ligated and encapsulated in a silicon tube allowing neuroma formation. Green fluorescent protein (GFP)-expressing Schwann cells (SCs) were injected proximal to the cut end of the nerve. Thirteen to 22 days after injury and SC injection, the L4 and L5 dorsal root ganglia (DRG) were prepared for acute culture. Whole cell patch-clamp recordings in current clamp mode were obtained and action potential properties of medium-sized (34-45 microm) FG+ DRG neurons were characterized. In the neuroma group without cell transplantation, action potential duration and spike inflections were reduced as were the amplitude and duration of spike afterhyperpolarizations. These changes were not observed after transection by nerve crush where axons were allowed to regenerate to distal peripheral targets. In the transplantation group, GFP(+)-SCs were extensively distributed throughout the neuroma, and oriented longitudinally along axons proximal to the neuroma. Changes in action potential properties were attenuated in the GFP(+)-SC group. Thus the engrafted SC procedure ameliorated the changes in action potential waveform of cutaneous primary afferents associated with target disconnection and neuroma formation.

Intradural ventral and ventrolateral tumors of the spinal cord: surgical treatment and results.

To improve results of surgical treatment of ventral and ventrolateral tumors of the spinal cord, the authors analyzed surgical approaches, defined the indications for various approaches, and assessed the clinical results. Between 1993 and 2004 the authors treated 360 patients: 43 of them had dorsal, 177 dorsolateral, 33 ventral, and 107 had ventrolateral intradural extramedullary tumors. Among 140 patients with intradural extramedullary ventral and ventrolateral tumors, neuromas were seen in 56 and meningiomas in 84. Of the 140 patients studied, tumors were removed totally in 102 (74%), subtotally in 30 (21%), and partially in eight (5%). After ventrolateral and dorsolateral approaches were introduced in 1996, tumors in ventral or ventrolateral locations have been removed totally or subtotally. In the group of patients with meningiomas, 41 of the lesions were the meningothelial type, 22 were transitional, 12 fibroblastic, four psammomatous, three were angiomatous, one was atypical, and one was malignant. Tumors in the neuroma group were schwannomas in 45 patients and neurofibromas in 11. Postoperatively, recovery was observed in 70 patients (50%), improvement in 53 (38%), no change in 10 (7%), and deterioration in seven (5%). At follow-up evaluation recovery was noted in 76 patients, improvement in 58, no change in four, and in two patients the neurological symptoms were worse than before the operation. Surgical routes to extramedullary tumors should be chosen based on the location of the tumor, its spread, and the region in which it is localized.

Receptors for NGF and GDNF are highly expressed in human peripheral nerve neuroma.

Immunhistochemistry of 10 traumatic human peripheral nerve neuromas and 5 normal digital nerves revealed a high immunoreactivity for the nerve growth factor (NGF) receptors p75 and trkA and the glial cell line-derived neurotrophic factor (GDNF) receptor GFRalpha-1. Semiquantitative image analysis showed a significantly increased trkA immunoreactivity in the neuroma group. The presence of the receptors may provide a way to influence therapy of peripheral nerve neuroma by administration of neurotrophins or other substances with binding sites similar to those of a neurotrophic factor.

Is hyperventilation-induced nystagmus more common in retrocochlear vestibular disease than in end-organ vestibular disease?

Hyperventilation-induced nystagmus (HVIN) has previously been shown by the senior author to be common in patients with both acoustic neuromas and following resection. The recurrent study's aim was to examine if HVIN was specific for retrocochlear pathology. To test this, the incidence of HVIN in 24 patients with confirmed acoustic neuroma was compared with its incidence in 38 patients with end-organ vestibular disease (defined as a greater than 25% reduction in caloric testing). Hyperventilation was carried out for 90 seconds. The results showed that 58% of the acoustic neuroma group were positive for HVIN versus 18% of the end-organ group. This difference was very significant on chi-square testing (p < .002). Hyperventilation-induced nystagmus appears to be much more prevalent in retrocochlear pathology than in end-organ pathology.

Dynamic Locomotor Function in Normals and Patients with Vertigo

Gait analysis was performed in patients with various vestibular systems using a tactile sensor. There were 4 patients with vestibular neuronitis, 6 patients with large acoustic neuroma and 6 patients with spino-cerebellar degeneration (SCD). Gait phase related parameters such as stance, swing and double support were studied to assess gait stability. Also the area ratio of trajectories of center of force during stance and progression of foot pressure were checked. The calculated value of each variable became high in pathological cases compared with normal controls, and the highest value was obtained in the SCD group. As regards the effect of visual deprivation on stability of gait, the most striking change was found in the large acoustic neuroma group. In a case with a unilateral lesion such as vestibular neuronitis and large acoustic neuroma, foot pressure was greater on the lesion side, especially during gait with eyes closed. As for the foot pressure progression curve, the SCD group showed the most irregular pattern in general, although there were some individual variations. Those results could reflect a functional disorder of the gait control system caused by each disease. Significance of gait analysis is also discussed.

Comparison of vestibular autorotation and caloric testing

The two most common stimuli of the vestibular system for diagnostic purposes are caloric and rotational head movements. Caloric stimulation, by delivering thermal energy to the lateral semicircular canal, is a well-studied method of vestibular testing, and its clinical usefulness has been established. Vestibular autorotation testing uses high-frequency (2 to 6 Hz), active head movements to stimulate the horizontal and vertical vestibulo-ocular reflex to produce measurable eye movements that can be used to calculate gain and phase. We compared the alternate bilateral bithermal caloric results with the vestibular autorotation test results obtained from 39 patients with peripheral vestibular disorders and from 10 patients with acoustic neuroma. In the peripheral disorder group, only 2 of 14 patients with equal caloric response ( < 20% reduced vestibular response) had a normal vestibular autorotation test result. No patients with a reduced vestibular response greater than 21% had a normal vestibular autorotation test result. In the acoustic neuroma group, four patients had a normal reduced vestibular response, but all patients had an abnormal vestibular autorotation test result. We conclude that testing both the horizontal and vertical vestibulo-ocular reflexes in their physiologic frequency range with the vestibular autorotation test provides additional information that could be missed by conventional caloric testing. Therefore high-frequency rotational testing is a valuable addition to the vestibular test battery. (OTOLARYNGOL HEAD NECK SURG 1995;113:215-22.)

Comparative Study on Gait Abnormality in Patients with Vestibular Neuronitis and Patients with Large Acoustic Neuroma

A comparative study on gait analysis comprising 11 patients with vestibular neuronitis and 10 patients with large acoustic neuroma was undertaken by the use of foot switches and electromyography. Central disorders in the neuroma group were evidenced by neurotological examinations. Fourteen healthy adults served as controls. Variables employed for the analysis were time from heel strike to forefoot strike (HA-I), time from heel off to forefoot off (HA-II) as well as duration of stance, swing and double supports (DS), location of maximum contraction of the gastrocnemius during stance, and location of the first and second peak of muscle contraction of the tibialis anterior from early swing phase (TA-off) to early stance phase (TA-on). The occurrence rate of abnormality of HA-I was the highest in both groups and most of the variables showed a higher rate in the large acoustic neuroma cases. In addition, a significantly higher CV value was obtained in HA-II of the lesion side's foot in the AN group. These changes could reflect the pathophysiological difference in the gait control systems between the two groups.

Metatarsus proximus and digital divergence. Association with intermetatarsal neuromas

A retrospective radiologic study was performed to determine whether there is an increased finding of metatarsus proximus and digital divergence in patients with a confirmed diagnosis of intermetatarsal neuroma when compared with an asymptomatic group. The study included 48 patients with pathologic confirmation of neuroma and 100 asymptomatic patients. Results of the study revealed no statistical relationship between the radiologic findings of metatarsus proximus and digital divergence and the physical occurrence of neuromas. An unexpected finding was an increased intermetatarsal angle of the affected interspace in the neuroma group.