Made by DATEXIS (Data Science and Text-based Information Systems) at Beuth University of Applied Sciences Berlin
Deep Learning Technology: Sebastian Arnold, Betty van Aken, Paul Grundmann, Felix A. Gers and Alexander Löser. Learning Contextualized Document Representations for Healthcare Answer Retrieval. The Web Conference 2020 (WWW'20)
Funded by The Federal Ministry for Economic Affairs and Energy; Grant: 01MD19013D, Smart-MD Project, Digital Technologies
The objective of irradiation is to halt the growth of the acoustic neuroma tumour, it does not excise it from the body, as the term 'radiosurgery' or 'gammaknife' implies. Radiosurgery is only suitable for small to medum size tumors.
There are three modalities of surgical treatment (excision) depending on where the anatomical location of the incision to access the tumor is made: retrosigmoid (a variant of what was formerly called suboccipital), translabyrinthine, and middle fossa.
The goals of surgery are to control the tumor, and preserve hearing as well as facial nerves. Especially in the case of larger tumors, there may be a tradeoff between tumor removal and preservation of nerve functionality.
There are different defined degrees of surgical excision, termed 'subtotal resection', 'radical subtotal resection', 'near-total resection', and 'total resection' in order or increasing proportion of tumor removed. Lesser amount of tumor removal may increase likelihood of preservation of nerve function (hence better post-operative hearing), but also likelihood of tumor regrowth, necessitating additional treatment.
There are several different surgical techniques for the removal of acoustic neuroma. The choice of approach is determined by size of the tumour, hearing capability, and general clinical condition of the patient.
- The retrosigmoid approach offers some opportunity for the retention of hearing.
- The translabyrinthine approach will sacrifice hearing on that side, but will usually spare the facial nerve. Post-operative cerebrospinal fluid leaks are more common.
- The middle fossa approach is preferred for small tumours, and offers the highest probability of retention of hearing and vestibular function.
- Less invasive endoscopic techniques have been done outside of the United States for some time. Recovery times are reported to be faster. However, this technique is not yet mainstream among surgeons in the US.
Larger tumors can be treated by either the translabyrinthine approach or the retrosigmoid approach, depending upon the experience of the surgical team. With large tumors, the chance of hearing preservation is small with any approach. When hearing is already poor, the translabyrinthine approach may be used for even small tumors. Small, lateralized tumours in patients with good hearing should have the middle fossa approach. When the location of the tumour is more medial a retrosigmoid approach may be better.
Auditory canal decompression is another surgical technique that can prolong usable hearing when a vestibular schwannoma has grown too large to remove without damage to the cochlear nerve. In the IAC (internal auditory canal) decompression, a middle fossa approach is employed to expose the bony roof of the IAC without any attempt to remove the tumor. The bone overlying the acoustic nerve is removed, allowing the tumour to expand upward into the middle cranial fossa. In this way, pressure on the cochlear nerve is relieved, reducing the risk of further hearing loss from direct compression or obstruction of vascular supply to the nerve.
Radiosurgery is a conservative alternative to cranial base or other intracranial surgery. With conformal radiosurgical techniques, therapeutic radiation focused on the tumour, sparing exposure to surrounding normal tissues. Although radiosurgery can seldom completely destroy a tumor, it can often arrest its growth or reduce its size. While radiation is less immediately damaging than conventional surgery, it incurs a higher risk of subsequent malignant change in the irradiated tissues, and this risk in higher in NF2 than in sporadic (non-NF2) lesions.
Early diagnosis allows better planning of therapy in young patients with NF II. In many cases, the hearing loss is present for 10 years before the correct diagnosis is established. Early in the condition, surgery for an acoustic neurinoma can protect facial nerve function in many patients. In selected cases of patients with very small tumors and good bilateral hearing, surgery may offer the possibility of long-term hearing preservation.
Patients with the Wishard phenotype suffer multiple recurrences of the tumour after surgical treatment. In the case of facial nerve palsy, the muscles of the eyelids can lose their mobility, leading to conjunctivitis and corneal injury. "Lidloading" (implantation of small magnets, gold weights, or springs in the lid) can help prevent these complications. Other means of preserving corneal health include tarsorrhaphy, where the eyelids are partially sewn together to narrow the opening of the eye, or the use of punctal plugs, which block the duct that drains tears from the conjunctival sac. All these techniques conserve moisture from the lacrymal glands, which lubricates the cornea and prevents injury. Most patients with NF II develop cataracts, which often require replacement of the lens. Children of affected parents should have a specialist examination every year to detect developing tumors. Learning of sign language is one means of preparation for those that will most probably suffer complete hearing loss.
Treatment of THS includes immunosuppressives such as corticosteroids (often prednisolone) or steroid-sparing agents (such as methotrexate or azathioprine).
Radiotherapy has also been proposed.
There are three treatment options available to a patient. These options are observation, microsurgical removal and radiation (radiosurgery or radiotherapy). Determining which treatment to choose involves consideration of many factors including the size of the tumor, its location, the patient's age, physical health and current symptoms. About 25% of all acoustic neuromas are treated with medical management consisting of a periodic monitoring of the patient's neurological status, serial imaging studies, and the use of hearing aids when appropriate.
One of the last great obstacles in the management of acoustic neuromas is hearing preservation and/or rehabilitation after hearing loss. Hearing loss is both a symptom and concommitant risk, regardless of the treatment option chosen.
Treatment does not restore hearing already lost, though there are a few rare cases of hearing recovery reported.
A diagnosis of NF2 related bilateral acoustic neuromas creates the possibility of complete deafness if the tumors are left to grow unchecked. Preventing or treating the complete deafness that may befall individuals with NF2 requires complex decision making. The trend at most academic U.S. medical centers is to recommend treatment for the smallest tumor which has the best chance of preserving hearing. If this goal is successful, then treatment can also be offered for the remaining tumor. If hearing is not preserved at the initial treatment, then usually the second tumor, in the only-hearing ear, is just observed. If it shows continued growth and becomes life-threatening, or if the hearing is lost over time as the tumor grows, then treatment is undertaken. This strategy has the highest chance of preserving hearing for the longest time possible.
Botulinum toxin is highly effective in the treatment of hemifacial spasm. It has a success rate equal to that of surgery, but repeated injections may be required every 3 to 6 months. The injections are administered as an outpatient or office procedure. Whilst side effects occur, these are never permanent. Repeated injections over the years remain highly effective. Whilst the toxin is expensive, the cost of even prolonged courses of injections compares favourably with the cost of surgery. Patients with HFS should be offered a number of treatment options. Very mild cases or those who are reluctant to have surgery or Botulinum toxin injections can be offered medical treatment, sometimes as a temporary measure. In young and fit patients microsurgical decompression and Botulinum injections should be discussed as alternative procedures. In the majority of cases, and especially in the elderly and the unfit, Botulinum toxin injection is the treatment of first choice. Imaging procedures should be done in all unusual cases of hemifacial spasm and when surgery is contemplated. Patients with hemifacial spasm were shown to have decreased sweating after botulinum toxin injections. This was first observed in 1993 by Khalaf Bushara and David Park. This was the first demonstration of nonmuscular use of BTX-A. Bushara further showed the efficacy of botulinum toxin in treating hyperhidrosis (excessive sweating). BTX-A was later approved for the treatment of excessive underarm sweating. This is technically known as severe primary axillary hyperhidrosis – excessive underarm sweating with an unknown cause which cannot be managed by topical agents (see focal hyperhidrosis).
Mild cases of hemifacial spasm may be managed with sedation or carbamazepine (an anticonvulsant drug). Microsurgical decompression and botulinum toxin injections are the current main treatments used for hemifacial spasm.
Since acoustic neuromas tend to be slow-growing and are benign tumors, careful observation over a period of time may be appropriate for some patients. When a small tumor is discovered in an older patient, observation to determine the growth rate of the tumor may be indicated if serious symptoms are not present. There is now good evidence from large observational studies that suggest many small tumors in older individuals do not grow, thus allowing tumors with no growth to be observed successfully. If the tumor grows, treatment may become necessary.
Another example of a group of patients for whom observation may be indicated includes patients with a tumor in their only hearing or better hearing ear, particularly when the tumor is of a size that hearing preservation with treatment would be unlikely. In this group of patients, MRI is used to follow the growth pattern. Treatment is recommended if either the hearing is lost or the tumor size becomes life-threatening, thus allowing the patient to retain hearing for as long as possible.
Current studies suggest surgeons should observe small acoustic neuromas (those 1.5 cm or less).
Over a period of 10 years of observation with no treatment, 45% of patients with small tumors (and therefore minimal symptoms) lose functional hearing on the affected side; this percentage is considerably higher than that for patients actively treated with hearing-preserving microsurgery or radiosurgery.
The prognosis of THS is usually considered good. Patients usually respond to corticosteroids, and spontaneous remission can occur, although movement of ocular muscles may remain damaged. Roughly 30–40% of patients who are treated for THS experience a relapse.
The tumor must be removed with as complete a surgical excision as possible. In nearly all cases, the ossicular chain must be included if recurrences are to be avoided. Due to the anatomic site of involvement, facial nerve paralysis and/or paresthesias may be seen or develop; this is probably due to mass effect rather than nerve invasion. In a few cases, reconstructive surgery may be required. Since this is a benign tumor, no radiation is required. Patients experience an excellent long term outcome, although recurrences can be seen (up to 15%), especially if the ossicular chain is not removed. Although controversial, metastases are not seen in this tumor. There are reports of disease in the neck lymph nodes, but these patients have also had other diseases or multiple surgeries, such that it may represent iatrogenic disease.
Treatment with the steroid "prednisone" and the antiviral drug "acyclovir 800mg 5 times a day" is controversial, with some studies showing to achieve complete recovery in patients if started within the first three days of facial paralysis, with chances of recovery decreasing as treatment was delayed. Delay of treatment may result in permanent facial nerve paralysis. However, some studies demonstrate that even when steroids are started promptly, only 22% of all patient achieve full recovery of facial paralysis.
Treatment apparently has no effect on the recovery of hearing loss. Diazepam is sometimes used to treat the vertigo.
The first aims of management should be to identify and treat the cause of the condition, where this is possible, and to relieve the patient's symptoms, where present. In children, who rarely appreciate diplopia, the aim will be to maintain binocular vision and, thus, promote proper visual development.
Thereafter, a period of observation of around 9 to 12 months is appropriate before any further intervention, as some palsies will recover without the need for surgery.
This is most commonly achieved through the use of fresnel prisms. These slim flexible plastic prisms can be attached to the patient's glasses, or to plano glasses if the patient has no refractive error, and serve to compensate for the inward misalignment of the affected eye. Unfortunately, the prism only correct for a fixed degree of misalignment and, because the affected individual's degree of misalignment will vary depending upon their direction of gaze, they may still experience diplopia when looking to the affected side. The prisms are available in different strengths and the most appropriate one can be selected for each patient. However, in patients with large deviations, the thickness of the prism required may reduce vision so much that binocularity is not achievable. In such cases it may be more appropriate simply to occlude one eye temporarily. Occlusion would never be used in infants though both because of the risk of inducing stimulus deprivation amblyopia and because they do not experience diplopia.
Other management options at this initial stage include the use of botulinum toxin, which is injected into the ipsilateral medial rectus (botulinum toxin therapy of strabismus). The use of BT serves a number of purposes. Firstly, it helps to prevent the contracture of the medial rectus which might result from its acting unopposed for a long period. Secondly, by reducing the size of the deviation temporarily it might allow prismatic correction to be used where this was not previously possible, and, thirdly, by removing the pull of the medial rectus it may serve to reveal whether the palsy is partial or complete by allowing any residual movement capability of the lateral rectus to operate. Thus, the toxin works both therapeutically, by helping to reduce symptoms and enhancing the prospects for fuller ocular movements post-operatively, and diagnostically, by helping to determine the type of operation most appropriate for each patient.
Practical surgical procedures used for treating synkinesis are neurolysis and selective myectomy. Neurolysis has been shown to be effective in relieving synkinesis but only temporarily and unfortunately symptoms return much worse than originally. Selective myectomy, in which a synkinetic muscle is selectively resected, is a much more effective technique that can provide permanent relief and results in a low recurrence rate; unfortunately, it also has many post-operative complications that can accompany including edema, hematoma, and ecchymosis. Therefore, surgical procedures are very minimally used by doctors and are used only as last-resort options for patients who do not respond well to non-invasive treatments.
The main treatment modalities are surgery, embolization and radiotherapy.
Botox (botulinum toxin) is a new and versatile tool for the treatment of synkinesis. Initially used for reducing hyperkinesis after facial palsy, Botox was later attempted on patients with post-facial palsy synkinesis to reduce unwanted movements. The effects of Botox have shown to be remarkable, with synkinetic symptoms disappearing within 2 or 3 days. The most common treatment targets are the orbicularis oculi, depressor anguli oris (DAO), mentalis, platysma and the contralateral depressor labii inferioris muscles. Due to the short span of Botox effects though, patients must come back to the doctor for re-injection approximately every 3 months. More notable is that in a majority of patients, various synkinetic movements completely disappeared after 2-3 sessions of trimonthly Botox injections.
A more specific synkinesis, crocodile tears syndrome (hyperlacrimation upon eating), has been shown to respond exceedingly well to Botox injection. Botox is injected directly into the lacrimal gland and has shown to reduce hyperlacrimation within 24–48 hours. The procedure was shown to be simple and safe with very little chance of side-effects (although on rare occasions ptosis can occur due to botulinum toxin diffusion). Furthermore, reduction in hyper-lacrimation was shown to last longer than the expected 3 months (about 12 months).
Since Botox can mimic facial paralysis, an optimized dose has been determined that reduces involuntary synkinesis of the muscle while not affecting muscle tone.
Treatment of people believed to have ATN or TN is usually begun with medication. The long-time first drug of choice for facial neuralgia has been carbamazepine, an anti-seizure agent. Due to the significant side-effects and hazards of this drug, others have recently come into common use as alternatives. These include oxcarbazepine, lamotrigine, and gabapentin. A positive patient response to one of these medications might be considered as supporting evidence for the diagnosis, which is otherwise made from medical history and pain presentation. There are no present medical tests to conclusively confirm TN or ATN.
If the anti-seizure drugs are found ineffective, one of the tricyclic antidepressant medications such as amitriptyline or nortriptyline, may be used. The tricyclic antidepressants are known to have dual action against both depression and neuropathic pain. Other drugs which may also be tried, either individually or in combination with an anti-seizure agent, include baclofen, pregabalin, anti-seizure drugs (to calm nerve endings), muscle relaxants, and opioid drugs such as oxycodone or an oxycodone/paracetamol combination.
For some people with ATN opioids may represent the only viable medical option which preserves quality of life and personal functioning. Although there is considerable controversy in public policy and practice in this branch of medicine, practice guidelines have long been available and published.
The evidence for surgical therapy is poor. Surgery is normally recommended only after medication has proved ineffective, or if side effects of medication are intolerable. While there may be pain relief after surgery, there is also a considerable risk of side effects, such as facial numbness after the procedure. Microvascular decompression appears to result in the longest pain relief. Percutaneous radiofrequency thermorhizotomy may also be effective as may stereotactic radiosurgery; however the effectiveness decreases with time.
Surgical procedures can be separated into non-destructive and destructive:
Overall, the mainstay of the treatment for salivary gland tumor is surgical resection. Needle biopsy is highly recommended prior to surgery to confirm the diagnosis. More detailed surgical technique and the support for additional adjuvant radiotherapy depends on whether the tumor is malignant or benign.
Surgical treatment of parotid gland tumors is sometimes difficult, partly because of the anatomical relationship of the facial nerve and the parotid lodge, but also through the increased potential for postoperative relapse. Thus, detection of early stages of a tumor of the parotid gland is extremely important in terms of prognosis after surgery.
Generally, benign tumors of the parotid gland are treated with superficial(Patey's operation) or total parotidectomy with the latter being the more commonly practiced due to high incidence of recurrence. The facial nerve should be preserved whenever possible. The benign tumors of the submandibular gland is treated by simple excision with preservation of mandibular branch of the trigeminal nerve, the hypoglossal nerve, and the lingual nerve. Other benign tumors of minor salivary glands are treated similarly.
Malignant salivary tumors usually require wide local resection of the primary tumor. However, if complete resection cannot be achieved, adjuvant radiotherapy should be added to improve local control. This surgical treatment has many sequellae such as cranial nerve damage, Frey's syndrome, cosmetic problems, etc.
Usually about 44% of the patients have a complete histologic removal of the tumor and this refers to the most significant survival rate.
Where an underlying neoplasm is the cause, treatment of this condition is indicated in order to reduce progression of symptoms. For cases without a known cause, treatment involves suppression of the immune system with corticosteroid treatment, intravenous immunoglobulin, immunosuppressive agents like Rituximab, Cellcept, or Imuran or plasmapheresis.
Patients treated with complete surgical excision can expect an excellent long term outcome without any problems. Recurrences may be seen in tumors which are incompletely excised.
Corticosteroids such as prednisone improve recovery at 6 months and are thus recommended. Early treatment (within 3 days after the onset) is necessary for benefit with a 14% greater probability of recovery.
Shingles is prevented by immunizing against the causal virus, varicella zoster, for example through Zostavax, a stronger version of chickenpox vaccine.
All destructive procedures will cause facial numbness, post relief, as well as pain relief.
- Percutaneous techniques which all involve a needle or catheter entering the face up to the origin where the nerve splits into three divisions and then damaging this area, purposely, to produce numbness but also stop pain signals. These techniques are proven effective especially in those where other interventions have failed or in those who are medically unfit for surgery such as the elderly.
- Balloon compression - inflation of a balloon at this point causing damage and stopping pain signals.
- Glycerol injection- deposition of a corrosive liquid called glycerol at this point causes damage to the nerve to hinder pain signals.
- Radiofrequency thermocoagulation rhizotomy - application of a heated needle to damage the nerve at this point.
- Stereotactic radiosurgery is a form of radiation therapy that focuses high-power energy on a small area of the body