Home

Spinal cord surgery recovery time

The methods used to fuse the vertebrae can vary depending on the needs of the patient. Therefore the recovery time can also vary. Typically patients stay in the hospital for 2-4 days after surgery and can return to work within 6-12 weeks, depending on their job requirements. LLIF / XLIF Surgery Recovery Time The recovery from the effects of the spinal tumor surgery itself is fairly standard and typically lasts about three to four weeks, no matter the type of tumor. Types of Spinal Tumors An important factor in determining the length of your recovery from spinal tumor surgery is the particular anatomic location of the tumor involved Spinal decompression surgery recovery time can vary depending on the complexity of your surgery and what procedures are being used to treat your spinal compression. Procedures used for spinal decompression There are three procedures that are widely used for spinal decompression surgery

Recovery from a spinal cord injury will depend on how severe the injury is. Spinal cord injuries usually involve long periods of rehabilitation and recovery. Treatment begins immediately after the.. If you get spinal fusion surgery, After Spinal Fusion Surgery. You'll need a longer recovery time after this procedure than you would after vertebroplasty or kyphoplasty. During the. Recovery from paraplegia after the treatment of spinal dural arteriovenous fistula: case report and review of the literature Acta Neurochir (Wien) . 2009 Nov;151(11):1385-97. doi: 10.1007/s00701-009-0439-6

These guidelines often differ depending on surgical procedure. For instance, if a traditional fusion surgery is performed, recovery time will be longer and thus differ from a less invasive, motion preserving spine procedure. If pain is allowed to get out of control, the activities will be difficult to perform and recovery will slow down Recovery after a discectomy generally takes six to eight weeks, according to Theresa Marko, a New York City doctor of physical therapy with board certification in orthopaedic physical therapy. Bouncing back from laminectomy or fusion surgery, however, takes longer Spinal cord injury recovery primarily focuses on promoting neuroplasticity through massed practice. Neuroplasticity is the spinal cord's ability to rewire itself and make adaptive changes so that functions affected by damage can be relearned. However, only undamaged neural pathways are capable of utilizing neuroplasticity The hospital will call you the afternoon before surgery with your surgery time. If your surgery is scheduled for Monday, you will receive a call on Friday. Please plan to report to the Ambulatory Surgical Unit (ASU) on the 5th floor of the Galter Pavilion (675 N. St. Clair) at least 2 hours prior to this time Recovery time is an important consideration for many patients considering spinal fusion. The emergence of minimally invasive surgery has impacted all types of surgery—back fusion surgery included—for the better, lessening the incision pain in the hours that follow. Surgeons can perform procedures through smaller exposures

What's the Typical Recovery Time for Spine Surgery

  1. Most patients after spinal cord stimulator surgery complain of pain and discomfort at the incisional sites. During the surgery, local anesthetic will be used at the site of the incisions and the pain relief effect should last about 6 hours. It is not uncommon to have incisional pain or discomfort later that evening and especially the day after surgery
  2. rareearth 15 Nov 2018 Your recovery time from this procedure should be no more than one week to four weeks. I offer up the longer time frame because many things can happen after surgery and we all react differently. I know patients who have had this procedure done and been back at work within two or three days, while some have taken longer
  3. Surgery Some spinal tumors, benign or malignant, require surgical intervention before or after non-operative treatments. When pain is unresponsive to non-operative treatment, neurologic deficit progresses, a specimen is needed, neural elements (e.g. nerves) are compressed, vertebral destruction exists, or when spinal stabilization is necessary - surgery is considered
  4. Tethered spinal cord is often linked to spina bifida. More than 40 percent of children who have spina bifida will need surgery to untether the spinal cord during their lifetimes. In most of those cases, the spinal cord is tethered to the tough membrane called the dura, which covers the spinal cord. Other causes of tethered cord syndrome include
  5. Recovery Time by Procedure When it comes to recovery time, not all spine surgery is created equal. Traditional spine surgery requires the physician to open the back to access the spine, creating a wound several inches in length. In open back surgery, removal or fusion of bone is fairly common, as is the addition of hardware to the spine
  6. g (if needed). Spinal Cord Stimulator therapy is reversible. If at any time you decide that you want to discontinue this therapy, the lead and generator can be removed
  7. The spinal cord contains many different nerves at each level and they may become irritated or compressed if there is an abnormality within the spine. Usually, this is down to an issue with your discs, which are jelly-like, soft structures within your spine, effectively cushioning the bones that make up the spine

Dr. Jarrod Kaufman answered. 29 years experience General Surgery. Syrinx: You would need to see a spine surgeon or neurosurgeon. Send thanks to the doctor. 90,000 U.S. doctors in 147 specialties are here to answer your questions or offer you advice, prescriptions, and more. Get help now As with any surgery—even a minimally invasive one—the initial recovery period following spinal cord stimulation implantation can be painful. Light activities can often be resumed after two to three weeks, but complete recovery may take six to eight weeks Spinal cord compression can occur anywhere from your neck (cervical spine) down to your lower back (lumbar spine). Symptoms include numbness, pain, and weakness. Depending on the cause of the compression, symptoms may develop suddenly or gradually, and they may require anything from supportive care to emergency surgery

How Long Does Recovery From Spinal Tumor Surgery Take

Recovery time depends on overall health and the amount of surgery needed. Help will be needed at home for daily household tasks and to help care for surgical wounds. It may take a few weeks to return to normal activity with a slow increase to normal activity. Additional rehabilitation, including physical and/or occupational therapy, may be needed The improvement in symptoms may not be seen immediately after the spinal decompression procedure but is seen over a period of time. For a young active individual it may take anywhere between one to three months for complete recovery from spinal stenosis surgery, and in cases where the individual is more sedentary and aged, it may take anywhere. Depending on the surgery, your total recovery time can vary. For example, it can take between 6 and 12 months for a spinal fusion to become solid. Sticking closely to your recovery plan can greatly..

Also, the surgery is more to go through since a fusion is an open procedure, and it takes about six to nine months or more for the fusion to heal. Read more: Lumbar Spinal Fusion Surgery Typically, the decompression and fusion are done as part of the same operative procedure Length of recovery can vary from two to four weeks or less to resume a sedentary job, or up to eight to 12 weeks for more physically demanding roles that require heavy lifting. 5  During the first two weeks of recovery, you will likely have several restrictions in place to facilitate healing of the spine until it becomes more stable

Spinal Cord Stimulation for Chronic Back and Neck Pain

Spinal Decompression Surgery: Recovery Timelin

Spinal Cord Stimulator (SCS) systems are designed to improve your quality of life and decrease your symptoms of chronic pain. The latest versions have allowed many patients to stop or significantly reduce oral medication intake. It's why SCS is one of the treatment methods we use for our chronic pain patients here in Greater New Orleans Find tips about recovering from a Spinal Cord Stimulator (SCS) procedure, giving your incision time to heal, resuming activities and more Recovery Time and Care. Usually, the most important part of the recovery process from a spinal cord stimulator implant surgery occurs in the first one to two weeks, but this can vary depending on the patient. During the recovery, the board certified doctors at Physician Partners of America will first provide you with a list of activities to avoid What is the recovery time after having a Spinal Cord Stimulator Battery replaced. 1 doctor answer • 2 doctors weighed in Connect with a U.S. board-certified doctor by text or video anytime, anywhere

Spinal cord injury: Recovery, stages, and suppor

Factors contributing to a healthy recovery. Bone spur surgery in the spine generally takes one of two forms: traditional open spine procedures or minimally invasive spine surgery. The goal of both forms of surgery is to relieve nerve compression caused by the growth of spinal bone spurs Spinal stenosis surgery may include one or more of the following: 3 . Discectomy: a procedure to remove a damaged disc between vertebrae of the spine. Laminectomy: a procedure to remove a portion of the vertebrae, especially if there is a bone spur. Foraminotomy: a procedure to widen the foramina, the openings in the vertebrae where the. Spinal Cord Stimulator Surgery. Spinal cord stimulators require two procedures to test and implant the device: the trial and the implantation. Spinal Cord Stimulator Trial. The first step is a trial period. Your surgeon will implant a temporary device for you to test out Spinal cord injuries affect between four and five million Americans per year, and about 400,000 people are living with the effects of spinal cord injury right now. While spinal cord injuries are more prevalent among males between the ages of 16 and 30, when all is said and done spinal cord injuries affect people from all walks of life, of all ages

Anterior Cervical Discectomy and Fusion (ACDF) is a surgery that relieves spinal cord and nerve compression in the neck by removing a degenerative or herniated disc.It's a common, relatively safe procedure that often results in long-term success. While ACDF recovery time can depend on the individual, there are typical steps that most people can expect to experience in the weeks and month. The spinal cord injury rehabilitation phase will provide the tools necessary to begin working toward independence. This is a critical time for recovery because many of the gains the patient will make in movement happen during this time Recovery From Surgery for Tethered Cord Syndrome With a Normally Positioned Conus in Children Postoperative Orders HOB , positioning, activity, bathing: The patient is kept flat on bed rest for 3 days to allow for dural healing and to put as little CSF pressure on the dura as possible during this time

Spinal decompression surgery covers several different surgeries that all have the same goal—to relieve the symptoms of spinal nerve compression. Spinal nerve compression refers to pressure on the spinal cord or spinal nerve roots. Spinal nerve roots are areas where bundles of nerves branch off the spinal cord and exit between two vertebrae For spinal stenosis, specific risks include: Possible infection, bleeding, or blood clots. A tear in the membrane that covers the spinal cord. Nerve damage. Recovery. Some people need to stay in. Recovery from spinal cord injuries can be predicted Date: March 7, 2018 Source: University of Zurich Summary: Injuries to the spinal cord result in tissue loss in the spinal cord and brain

This precise monitoring can help minimize risk to the spinal cord, nerves and nerve roots. The great majority of patients do well with surgery. Most stabilize or even improve their level of function. The spinal cord does have the potential to re-tether after surgery, though. For this reason, follow-up care is important after tethered cord surgery It is exactly 3 months since I had my surgery to remove a bone spur in my spinal cord, C4/C5. I have very little pain, although I feel pain in my neck when I sit in front of the computer. I sit, sleep, and stand without pain. My left leg and my left leg still has a lot of numbness and pain. I cannot walk properly. When I walk, I have a lot of pain Spinal instrumentation is done along with decompression which is a minimally invasive procedure performed to take pressure off the spinal cord or nerve roots. [Also Read: Difference Between Major and Minor Surgery ] Before inserting the hardware, your surgeon will remove the part of the spine that is pressing on the nerves Minimally Invasive Spine Surgery. In general, the goal of minimally invasive spine (MIS) surgery is to stabilize the vertebral bones and spinal joints and/or relieve pressure being applied to the spinal nerves — often a result of conditions such as spinal instability, bone spurs, herniated discs, scoliosis or spinal tumors Spinal instrumentation is performed by a neurosurgical and/or orthopedic surgical team with special experience in spinal operations. The surgery is done in a hospital under general anesthesia. It is done at the same time as spinal fusion

Tethered spinal cord syndrome is a neurologic disorder caused by tissue attachments that limit the movement of the spinal cord within the spinal column. These attachments cause an abnormal stretching of the spinal cord. This syndrome is closely associated with spina bifida. It is estimated that 20-50% of children with spina bifida defects that. The goal of surgery is to relieve symptoms by decompressing, or relieving pressure on, the spinal cord. This involves removing the pieces of bone or soft tissue (such as a herniated disk) that may be taking up space in the spinal canal. This relieves pressure by creating more space for the spinal cord. Candidates for Surgery

Video: Recovery From Spinal Compression Fracture Surger

Recovery from paraplegia after the treatment of spinal

Caring for a dog after spinal surgery requires a big time commitment. Your dog may need help relieving himself. Physical therapy is also on the agenda. massage. stretching exercises. range-of-motion exercises. and sitting to standing exercises. Caring for a dog after spinal surgery requires a big time commitment Acute spinal cord compression (ASCC) is a surgical emergency requiring immediate neurosurgical treatment. Prognosis of the condition can vary and is most dependent on the time between diagnosis and treatment. In this article, we shall look at the risk factors, clinical features and management of acute spinal cord compression A spinal stroke is caused by a disruption in the blood supply to the spine. Most of the time, this is a result of a narrowing of the arteries (blood vessels) that supply blood to the spinal cord

Neck/upper back surgery —the bed head is elevated 20 to 30 degrees for 24 to 48 hours for swelling. Keep the knees bent to reduce strain on the spinal cord. Use a pillow under knees. Resume normal flat bed position ASAP or very slight elevation only. Lower back surgery— keep the electronic bed head down Today is my 5 day of recovery with my spinal cord simulator permanent implant. I have a Medtronics with two leads

Spinal Stenosis. Spinal stenosis, a narrowing of the spaces in your spine, can compress your spinal cord and nerve roots exiting each vertebrae. Age-related changes in your spine is a common cause. Symptoms include back and/or neck pain, and numbness, tingling and weakness in your arms and legs. Treatments are self-care remedies, physical. In addition to reducing the need for spinal fusion, a minimally invasive approach to surgery has been shown to result in a shorter recovery time. In most cases, these space-creating operations help reduce spinal stenosis symptoms. But some people's symptoms stay the same or get worse after surgery

Only a small scar will form, resulting in a quicker recovery. Surgery on the core of the spinal disc: The surgeon uses instruments to access the core of the spinal disc then uses a vacuum to. The spinal cord stimulator device is comprised of two parts: thin wires, or electrodes, and a generator, which is like a pacemaker. Between 8 and 32 electrodes are implanted in between the vertebrae and the spinal cord and the generator is placed just beneath the skin. The patient has full control over the device It is estimated that approximately 30% of patients with spinal cord injuries have pressure injuries 20 years after the initial spinal cord injury. 2 In the post-operative period after pressure injury flap surgery, patients with spinal cord injuries can have intense muscle spasms caused by associated spasticity and leading to early loosening of. Schedule A Consultation. If you suffer from a spinal cyst, Dr. Lipani may offer the best treatment for you. Call our New Jersey office at 609-890-3400 to schedule a consultation at Princeton Neurological Surgery. » View Our Spinal Procedures Section

Recovery of lost muscle and bladder function is variable, and depends on both the degree and length of the neurologic losses before the surgery. Untethering is designed primarily to prevent further deterioration, not to improve spinal cord damage that has already occurred Jack Eichel's Neck Surgery & Recovery. New 7 cervical vertebrae that allow the spinal cord to pass through the middle, acting as a cage of sorts. an unexpected blow to the head/neck area.

Sometimes a spinal fusion is incorporated due to spinal instability after decompressing of the foramen. MIS Microdiscectomy - Is a surgery to remove herniated disc material that is compressing a nerve root or the spinal cord. This surgery is usually done as a microdiscectomy using a microscope or surgical loupes Spinal Cord Tumor Association. The Spinal Cord Tumor Association Facebook page is a closed group for people with tumors. They provide a supportive environment. www.spinalcordtumor.org. WalkTalkConnect. WalkTalkConnect is non-profit 501 (C) (3) dedicated to raising awareness of rare brain & spinal cord tumors affecting our central nervous system Thoracic Spinal Cord Injury Prognosis and Recovery. Prognosis and recovery from a thoracic spinal cord injury may differ from patient to patient. The difference is due to the type of injury and the level of severity. A patient's health is also a factor in determining the level of independence achieved after an injury

Prior to surgery, your dog undergoes X-rays and a myelogram -- an X-ray test that includes a dye injection around the spinal cord -- to locate the part of the spinal cord involved. During the operation, known as a hemilaminectomy, the surgeon removes a bone section above the spinal cord and removes the herniated material from the disc Syringomyelia (SM) is a disease in which there is a syrinx, or cyst, in the spinal cord. The syrinx is filled with cerebrospinal fluid (CSF). Due to normal activities like coughing and straining, SM cavities can slowly become larger over a period of time, often years. As the syrinx gets larger, it stretches the spinal cord and damages nerve tissue Roughly as thick around as the human thumb, the spinal cord is about 18 inches in length and runs from the brainstem to the first lumbar vertebrae enclosed within the spinal canal. At the base of the spinal cord is the cauda equina , where the cord fibers disperse and continue down through the tailbone into the legs and down into the feet Up until about 50 years ago, few people survived spinal cord injuries. Even today, spinal cord injuries are immediately fatal in a significant number of people. If you have survived, you're already well on the road to recovery. Critical Care, Surgery, and Hospitalization . The earliest days after your injury are often the most confusing

Kyphoplasty Recovery | Arizona Pain and Spine Institute

How to Best Recover for Spine Surgery when You're 65

What is the spinal cord stimulator removal recovery time? If you need to have your spinal cord stimulator removed, the spinal cord stimulator removal recovery time is generally brief. It should take between two to four weeks for complete healing, but as with all medical procedures this varies from patient to patient Patient Recovery Time after a Spinal Cord Stimulator Surgery. It is important to take it easy at home for a few weeks after your surgery. It is different for everyone, but most patients say that their recovery time is around 3 weeks. After your spinal cord stimulator surgery, you will have staples that need to be removed I planned for the worst but knew that wasn't necessarily going to happen. I began researching and coming up with a game plan if the surgery resulted in more complications. Recovering at NIH. My surgery lasted eight hours. I spent the first 24 hours following surgery in the ICU to make sure there was no spinal cord fluid build-up

Hi all. I'm 2 years into my CRPS diagnosis after herniating disc at C5/6..after surgery to remove disc, left at pain worsened, took some time but finally found my wonderful pain specialist who has been working tirelessly to get me a consult with neurosurgeon for SCS implantation Dural tear: If surgery disrupts the protective covering over the spinal cord and nerves, you could have a dural tear. Surgeons may detect and repair a dural tear during surgery, and most tears heal without an issue. If the tear does not heal properly, you may experience headaches from leaking spinal fluid

Do's and Don'ts for a Successful Back Surgery Recover

Surgery for a Tethered Spinal Cord. The most common treatment for tethered spinal cord is a lumbar laminectomy to release the tethered cord. For this procedure, the patient is placed under general anesthesia. The neurological surgeon makes an incision in the lower back to expose the site where the spinal cord is pinned, then frees it by. Spinal Fusion: Precautions, Procedure, Outcomes, & Recovery. by Dr. Craig Humphreys Jan 10, 2019. If you're a just the facts kind of person, here's a fact you might be interested in: Spinal surgery is only between 50% and 70% effective, compared to the 90+% positive outcomes for hip and knee surgeries, where joint replacement is common

We have the largest practice and the greatest experience in tethered spinal cord surgery in the surrounding seven-state region. Surgeons at Children's Colorado also use the latest technology to achieve the best outcomes. This includes technologies like the surgical microscope, operative laser and neurological monitoring Suze Orman gives advice for handling money issues during the pandemic. July 6, 202010:53. When she eventually had the tests, they found that 80% of her spinal cord was being cut off by a non. Spinal Fusion Surgery Recovery Time. This is a very complicated surgery and it can take four to six months to recover from spine surgery you are still going to have a lifetime of care. How long the recovery time will actually take is based on several factors like the recovery of compressed nerves as well as the muscle condition in your spine.

ACD&F (Anterior Cervical Discectomy and Fusion) -- Larry

Thoracic Spinal Cord Injury: What to Expect & How to Recove

Spondyloarthritis - Physiopedia

The definition of success for spinal cord stimulator is a 50% reduction in pain. This isn't a magic cure by anyone's measurement. But for those of us who suffer from chronic pain, a 50% pain. Laminectomy: Surgery for Back Pain. Pressure on the spinal cord and nerve roots can cause pain and numbness or tingling in the arms and legs. In the lower back (lumbar region) pressure on the nerve roots can lead to trouble walking and problems with bowel and bladder function. Laminectomy may be an option to help relieve your pain Surgery to remove lipomas and free a tethered spinal cord. On Oct. 18, 2017, 10-month-old Eva was taken to an operating room at Children's Hospital of Philadelphia, where Dr. Chen performed surgery to free Eva's spinal cord, and Jesse Taylor, MD, Chief of the Division of Plastic and Reconstructive Surgery, removed two of the lipomas The last step is closing the incision. Recovery starts thereafter. Spinal Cord Stimulator Recovery. Although this surgery is minimally invasive, the initial recovery period can be painful and uncomfortable. The patient can resume light activities two to three weeks after the surgery. However, normally, complete recovery takes up to eight weeks A spinal shunt (also known as a lumbar shunt) is designed to bypass, or redirect, bodily fluids from one point in the body to another. Two types of lumbar shunts include Lumbar-peritoneal (LP) and Lumbar-subcutaneous (LS), although the LP shunt is most common. Both types of spinal shunts are composed of tubing or a catheter and some variations include a valve for fluid output monitoring

Spinal cord abscess is the swelling and irritation (inflammation) and the collection of infected material (pus) and germs in or around the spinal cord. The vertebral column is made up of 26 bones that provide axial support to the trunk. The vertebral column provides protection to the spinal cord, which runs through its central cavity Aug 9, 2015. i am having a posterior lumbar 4-5 laminectomy with synovial cyst removal on August 27,2015. I have a 5 day trip to Germany planned 6 &1/2 weeks later. I now know the recovery to be longer than the one week I had thought. I know it is at least 6 weeks, after my pre surgery intake with the wonderful nurse I have Treatment for spinal cord compression should start as soon as possible, usually within 24 hours of diagnosis. This reduces the chance of permanent damage to the spinal cord. Treatment can also control symptoms of compression. Some people have pain. Other people have nerve symptoms, such as numbness or tingling Recovery after spinal cord stimulator implantation. Your recovery will depend on several factors, including your age, past surgeries, and health habits. Even though it is a quick procedure, there is a significant recovery time of six to eight weeks. During this time, it is vital that you listen to your body and go at a slower pace than usual

Spinal Fusion Recovery Time: An Analysis - BalancedBack

A compressed spinal cord can lead to paralysis if severe. Management of pinched nerves may include an initial trial of conservative care, including therapy, steroid injections, medication, and time. Surgery may be required if patients do not improve Back or leg pain, numbness or tingling may result when the disc material touches or compresses a spinal nerve. Treatment with rest, pain medication, spinal injections, and physical therapy is the first step to recovery. Most people improve in 6 weeks and return to normal activity. If symptoms continue, surgery may be recommended The practical application of these in various types of spine and spinal cord surgery were refined during the 1990s. 3,11-14 More recently, very strong evidence for the benefit of MEP monitoring for spinal cord surgery was reported. 15. Neurophysiolog For instance, C7 and C6 spinal cord injury exercises may help speed up recovery. Surgery is done to stabilize the area around the spinal cord damage. The nerves around the damage are decompressed in hopes of relieving some of the symptoms. Fusion is then achieved by fixing the areas in and around the spinal cord damage

Healing time after spinal cord stimulator battery replacement

The brain and spinal cord are surrounded by a clear fluid called cerebrospinal fluid (CSF). The CSF supports and protects the brain and the spinal cord. You might have surgery for hydrocephalus at the same time you have surgery to remove your tumour. Or you may have a separate operation. Having brain surgery might sound like a frightening. Numerous recent studies suggest that surgery also can be beneficial in individuals with persistent compression of the spinal cord and ongoing neurological deterioration. Prognosis The prognosis for central cord syndrome varies, but most people whose syndrome is caused by trauma have some recovery of neurological function These dogs tend to have severe spinal cord compression from IVDH, and their prognosis for full or near full recovery with spinal cord decompression is 90%+. That prognosis falls off the longer surgery is delayed

Lumbar Spinal Fusion – YanniSpinal cord stimulator trial, day 5 - YouTubeSpine Surgery Salem | Cervical Spine Surgery

Laminoplasty surgery can relieve pressure in your spinal canal or on your spinal cord of your neck or back by widening your spinal canal. Laminoplasty is an alternative to laminectomy. Laminectomy is the removal of all of the lamina. Unlike laminectomy, laminoplasty surgery preserves spinal stability because the lamina is not removed Spinal cord trauma may heal over time without further problems, or it may result in permanent deficits, depending on the location and severity of the injury. Early recovery of at least some movement or sensation suggests that additional recovery is possible The second option, a spinal shortening surgery, is used to avoid disturbing scar tissue or the location where the spinal cord is tethered. In this procedure, some or all of a vertebra in the spinal column is removed, reducing the strain on the spinal cord and in effect shortening a patient's height Animation of spinal cord surgery. Take a look at some of our other animation samples and video testimonials below to see why our clients choose MotionLit for.. Lumbar spinal fusion is a surgery to join two or more spinal bones — called vertebrae [VUR-tuh-brey] — so that they eventually grow into one solid bone. Why do I need spinal fusion? The surgery is usually done to correct instability of the spine. Arthritis, injuries, or simple wear and tear can cause som Not everyone with a Chiari malformation requires surgery, but when a patient's individual circumstances warrant it, a neurosurgeon may recommend decompression surgery (known as a decompressive suboccipital craniectomy and cervical laminectomy). As its name suggests, the goal of this procedure is to reduce or eliminate the pressure on the spinal cord caused by the cerebellar tonsils