Minimally Invasive Spine Surgery

Dr. Tredway was the first fellowship-trained minimally invasive spine neurosurgeon in Seattle.  He has been on the cutting edge of minimally invasive spinal surgery and has published numerous articles in this area.

Minimally invasive spine surgery allows surgeons to treat many conditions through small incisions using tubular retractors and utilizing an endoscope or a microscope. The reported outcomes in regard to complications, length of stay, pain level, as well as re-operation rate have been documented to be better than traditional open procedures.  As a nationally-recognized leader in this area, Dr. Tredway treats many of his patients with these techniques and often lectures and trains other surgeons throughout the country on minimally invasive procedures.  He is a founding member of the Society for Minimally Invasive Spine Surgery (SMISS).

Post operative X-ray with two artificial discs

Post operative X-ray after corpectomy and fusion with instrumentation

Minimally invasive decompression incision size compared to a dime

Our Services

Pre-op MRI with C4/5 and C5/6 Disc Herniations

Pre-op CT of L4/5 Spondylolisthesis

Post operative X-ray of 

realigned spinal deformity

Close up X-ray of cannulated screws

Pre-op MRI of L4/5 Spondylolisthesis

Pre-op MRI of thoracic intramedullary

spinal cord tumor

Post operative X-ray of realigned L4/5

Bilateral Sacroiliac Joint Arthodesis and Stabilization

Axial MRI of lumbar stenosis

Scoliosis and Deformity Surgery

Scoliosis of the spine can occur in adolescents as well as in older patients secondary to degenerative processes of the spine.  Some patients that have undergone previous surgical intervention can also develop a scoliotic deformity.  Many patients with scoliosis deal with their pain through conservative measures; however, some patients endure years of progressive pain with many of the patients becoming imbalanced.  These patients find it difficult to sit, stand, and walk for any period of time.  Some patients can be treated through minimally invasive techniques, but others may require an extensive surgical procedure that enables the surgeon to decompress the neural elements (spinal cord and nerve roots) as well as correct the deformity through placement of grafts and screws as to better align the patient's spine.  These surgeries are often quite extensive, but with careful planning and the use of intraoperative navigation (GPS-like technology) that allows the instrumentation to be placed in the correct position, patients can have outstanding outcomes with decreased morbidity (complications).

CT scan of calcified thoracic disc

Coronal MRI demonstrating scoliosis

Pre-op AP X-ray of scoliotic deformity

Intraoperative image of tubular retractor and endoscope

Thoracic Disc Herniations

Patients with thoracic disc herniations can present with unilateral, radiating pain as well as with weakness, numbness, and/or bowel, bladder, and sexual dysfunction.  Thoracic disc herniations (TDH) are extremely rare and comprise only about 1% of all disc herniations.  However, thoracic disc herniations are often difficult to treat and carry a high complication rate associated with surgical treatment.  Many new procedures have been developed to treat these disc herniations more safely and Dr. Tredway has pioneered techniques in treating patients with these difficult lesions.  He has lectured extensively about the treatment of thoracic disc herniations and has trained other surgeons on the different surgical techniques.

Intraoperative image of detethering

of cord with fatty filum

MRI of thoracic disc herniation

Tredway Spine Institute

Sagittal MRI of lumbar stenosis

Tethered Cord Syndrome

Patients with tethered cord syndrome usually present with pain, bowel/bladder issues, or tightness in the hamstrings. This is typically caused by a tethering of the distal spinal cord during early embryonic development.  Patients usually present with symptoms in their early teens, but some patients present with symptoms in adulthood.  Some patients also have a lipoma (fatty tumor) associated with their tethered cord.  The treatment for patients with tethered cord syndrome includes a detethering of the distal portion of the spinal cord.  Dr. Tredway has treated many patients for this syndrome and has co-authored the sentinel journal article on minimally invasive treatment of this condition.

Minimally Invasive and Open Surgical Treatment for Spondylolisthesis

Patients with spondylolisthesis (slipping of the superior vertebral body on the inferior vertebral body) often present with both low back pain (lumbago) and buttock and leg pain (lumbar radiculopathy or sciatica).  Spondylolisthesis can occur from a congenital defect in the spine, trauma, previous surgery (iatrogenic) , inflammation (arthritis), as well as from degenerative changes that occur as a process of aging.  Often, patients have a long indolent course and then develop worsening back and leg pain.  Conservative measures are often successful for a while; however, many patients start developing worsening symptoms that are not alleviated with the conservative measures.  At this time, patients are candidates for surgical intervention which usually includes a decompression (laminectomy and foraminotomy) to remove the compression on the nerve roots, as well as a reduction of the slip and stabilization using instrumentation (instrumented fusion).  This allows for re-alignment of the spine and can be very effective in reducing the pain and symptoms associated with spondylolisthesis.  Patients may be candidates for a minimally invasive procedure (Minimally Invasive Transforaminal Lumbar Interbody Fusion) or an open fusion (Gill Laminectomy with Open Reduction and Transforaminal Lumbar Fusion).  This type of procedure can yield excellent results with decreased hospital stay.

Axial MRI of patient with a tethered


Cervical Discectomy with Fusion and Cervical Disc Arthroplasty (Artificial Discs)

Patients presenting with cervical radiculopathy (arm pain, weakness, or numbness) are first treated with conservative measures including NSAIDs, physical therapy, spinal injections, as well as chiropractic manipulation.  If patients fail conservative measures, then surgical intervention in the form of an anterior cervical discectomy is performed to relieve the pressure of the offending disc fragment or osteophyte (bone spur) on the nerve root and spinal cord.  After performing the decompression and discectomy, the traditional surgery included placing a small piece of bone or graft and a plate to allow for a fusion to occur across the disc space.  This surgery has been extremely effective, but it does limit motion in the cervical spine and has also been shown to be associated with degenerative changes at the adjacent cervical levels (30% over a 10 year period).  This led surgeons and engineers to devise a motion preservation device, or artificial disc, to allow for movement at the surgical level as well as reduce the strain at the adjacent levels.  These devices are FDA-approved and have been shown to have a lower re-operation rate when compared to the fusion patients.  This type of surgery is specific for individuals that meet the radiographic and age criteria for the devices.

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Pre-op MRI with large disc herniations

Spinal Stenosis

Patients with lumbar spinal stenosis present with pain in the lower extremities, numbness and tingling in the legs (intermittent claudication), and/or weakness.  Spinal stenosis can occur in younger patients and is considered congenital stenosis if the spinal canal is abnormally small.  Most patients develop spinal stenosis with age as the degenerative processes that occur with aging cause narrowing of the spinal canal and compression on the nerve roots.  The combination of disc degneration, facet arthropathy (arthritis), and ligamentum flavum hypertrophy (buckling of the yellow ligament) create a narrowed space for the nerve roots.  This condition may be treated with conservative management, but often times surgical intervention in the form of a laminectomy is performed.  Dr. Tredway has written several articles and lectured extensively on minimally invasive treatments for patients with lumbar stenosis.

Post operative MRI after complete

resection of intramedullary spinal

cord tumor

Spinal Cord Tumors

Patients harboring spinal cord tumors often present with pain, weakness, and/or numbness.  The diagnosis is usually obtained from the clinical exam combined and an MRI of the spine.  These tumors are usually treated through surgical resection and excellent outcomes can be achieved.  Dr. Tredway has performed numerous spinal cord tumor resections over his career and employs microdissection techniques as well as intraoperative monitoring to achieve complete resections with low morbidity.  He has authored numerous articles and book chapters on spinal cord tumors and their surgical treatment.

Sacroiliac Joint Pain

Patients with sacroiliac joint pain typically present with pain in one or both SI joints and the pain is usually exacerbated with sitting or standing.  Patients may respond to conservative measures including physical therapy and chiropractic manipulation.  The diagnosis is made on clinical examination and often times a good response to a sacroiliac joint injection can help confirm the diagnosis.  If patients fail conservative therapy, then a sacroiliac joint arthrodesis with stabilization can be quite helpful in alleviating the pain.  Dr. Tredway has refined a technique of stabilizing the joint with a mini-open approach utilizing intraoperative navigation to place the screws across the SI joint.  The anatomy of the pelvis is quite variable and safely placing the screws is paramount to a good fusion and excellent outcome.