Spinal and Peripheral Nerve Surgery consists of surgical strategies and procedures to minimise pain and restore maximum range of motion in patients with spinal and peripheral nerve conditions such as degenerative disc disorder, traumatic spinal injury, herniated disc, spinal stenosis (narrowing) and spinal cord tumours. Surgical intervention can help minimise chronic pain, address spinal instability and help improve the patients range of movement and quality of life. Spinal surgery consists of a range of techniques such as decompression, spinal fusion, laminectomy etc. In most cases, these procedures can be performed using open or minimally-invasive technologies.
Anterior Cervical Discectomy and Fusion (ACDF)
Anterior Cervical Discectomy and Fusion is a surgical procedure used to repair a herniated or degenerative disc in the spine. The surgery aims to relieve pressure on the spinal cord or root nerves and reduce the consequent pain, numbness or tingling sensations. The procedure is commonly performed to treat symptomatic cervical herniated discs and cervical degenerative disease. It is also used to remove bone spurs caused by arthritis and alleviate symptoms associated with spinal stenosis.
The Anterior Cervical Discectomy and Fusion Surgery has 2 parts – The first part is the Anterior Cervical Discectomy, in which the cervical spine (neck) is accessed via a frontal (anterior) incision in order to remove the degenerated disc from in between the vertebral bones. The second part of the procedure is a Fusion Surgery to stabilise the cervical spine. This involves placing a bone graft in the intra-vertebral space previously occupied by the degenerated disc, to provide strength and stability. As the surgical site heals, the bone graft grows and provides stability and strength to the neck.
The Anterior Cervical Discectomy and Fusion Approach is advantageous because it allows direct visualisation and access to the cervical discs. The approach is relatively uncomplicated and hence results in less post-operative pain and lower chances of comorbidities.
Artificial Disc Replacement
An artificial disc is a biomedical implant placed in the intravertebral space, in place of a degenerated disc. The degenerated disc is surgically removed before the artificial disc is implanted. The goal of this procedure is to relieve back pain and recover a more normal range of motion, giving the patient a chance at a better quality of life. Artificial disc implants are effective at maintaining a better range of motion as compared to an anterior cervical discectomy and fusion (ACDF). Artificial disc replacements also typically have a lower recovery time compared to ACDF procedures.
During the artificial disc replacement procedure, the surgeon approaches the spine through an incision in the abdomen, moving the abdominal organs aside. This approach is favoured because the spinal nerve roots suffer minimal disturbance. The surgeon then removes the problematic disc and inserts the artificial disc in its intravertebral space. The artificial disc implant usually consists of a nucleus (core), and annulus (outer ring) and a mechanical device to stimulate spinal function.
Cervical/ Lumbar Laminectomy
The word “Lamina” refers to the back of the vertebra that covers the spinal cord. A Laminectomy is a procedure wherein a part of the lamina is removed to create an expanded space for the spinal cord and nerve roots. The aim of the procedure is to relieve pressure on the spinal cord. I It is also called a spinal decompression surgery. A laminectomy may be used to treat a traumatic spinal injury, herniated disc, spinal stenosis (narrowing of the spinal canal) and spinal cord tumours. The procedure is also used to remove bony spur formations on the vertebrae of the spine as a result of arthritis.A Laminectomy procedure is only recommended if conventional methods, such as drug therapies, physical therapies and injections, have failed to address symptoms; or if symptoms rapidly worsen.A laminectomy is a surgical procedure performed under general anaesthesia. The surgeon makes an incision on the back, along the affected vertebrae and retracts the back muscles away for better visualisation of the bones. Specific portions of the lamina are removed to relieve pressure on the spinal cord. If the disc is herniated, it is removed and replaced with a bone graft or artificial disc as decided by the physician in charge of the case. Laminectomies are performed in the cervical spine (neck) and the lumbar spine (lower back).
Lumbar decompression and fusion (PLIF, TLIF)
Lumbar spinal stenosis is a common cause of lower back and leg pain. Lumbar decompression and fusion surgeries are the most common procedures employed to treat this condition. The procedures involve 2 steps – Decompression, in which the bony structure constricting or pinching the spinal cord is removed to relieve pressure; and Fusion, in which a bone graft is placed to fuse the vertebrae adjacent to the decompression site for increased strength and stability of the spine.
There are multiple types of lumbar decompression and fusion procedures, based on the nature of the graft and the incision approach taken.
Posterior Lumbar Interbody Fusion (PLIF) is a lumbar decompression and fusion technique in which the spine is approached through an incision in the back and the graft used is an interbody graft. This type of graft is characterised by the metal spacer/cage (inside which the bone graft is placed) used to maintain the height of the vertebrae.
Transforaminal Lumbar Interbody Fusion is a variation of the PLIF technique, in which the approach is slightly tweaked, to approach the spine from the side, to minimise incising the back muscles and the nerve roots emerging from the spine. TLIF also uses an interbody fusion device as the bone graft implant.
Minimally invasive spine surgery (MISS)
Minimally invasive spinal surgery techniques are an alternative to conventional open surgical techniques. Minimally invasive spinal surgery is advantageous because of the quick recovery time, lower chances of comorbidities and reduced post-operative pain. Minimally invasive techniques are used to treat degenerative disc disease, herniated disc, spinal stenosis, spondylolysis, and scoliosis. With minimally invasive procedures , there is sometimes the option of performing certain spinal procedures on an out-patient basis as well.
The patient is usually given general anaesthesia before the procedure. The vital signs are carefully monitored throughout. The surgery is performed percutaneously or through micro-incisions in the skin. A tubular retractor is placed in the incision and endoscopic surgical tools and cameras are manoeuvred through it. Once the required repair is complete, the surgical incision is closed with stitches, surgical glue or staples.
Spinal cord tumours
Spinal cord tumours are small growths or masses of cells that form on the spinal cord, in the spinal canal or in the vertebrae. Spinal cord tumours are classified into various types depending on where they occur. A vertebral tumour is one that occurs on the bony vertebrae protecting the spinal cord. Extramedullary tumours grow in the membrane surrounding the spinal cord or in the nerve roots emerging from the spine. These growths can cause compression on the spine and other associated problems. Examples of extramedullary tumours are meningiomas, neurofibromas, schwannomas, and nerve sheath tumours. Intramedullary tumours occur in the core tissue of the spinal cord, like gliomas, astrocytoma and ependymomas. Tumours originating in other parts of the body, such as the abdomen, can also metastasise to the vertebrae and the spinal cord.
The course of treatment for spinal cord tumours is carefully decided based on the type of tumour, location, extent of spread and the general health of the patient. Non-surgical treatment options include radiation therapy and chemotherapy, both of which have proven effective in treating spinal cord tumours. For primary tumours in the spinal cord, complete surgical removal could be curative. In the case of metastasised tumours (tumours that have spread from another part of the body), removal may be only palliative, with the goal of preserving neurological function, reducing pain and stabilising the spine. For cases where the surgical removal of the tumour is possible, pre-operative embolization is recommended to make resection easier. During embolization, a catheter is inserted into tumour under fluoroscopy guidance, and a glue-like embolic agent is injected into the tumour. This compound blocks the blood supply to the tumour, effectively killing it. This helps control bleeding during surgery.
Peripheral nerve tumours
Peripheral nerve tumours are small masses of cells in the nerves that transmit signals from the spine to the various parts of the body. Peripheral nerve tumours could occur anywhere in the body. They are usually non-cancerous but nonetheless cause pain and loss of function . Peripheral nerve tumours are primarily classified into two types based on location – Intraneural tumours, which grow from within the nerve tissue, and Extra neural tumours, which grow on the tissue surrounding the nerve and exert pressure on it. Examples of benign peripheral nerve tumours include schwannoma, neurofibroma, ganglion cysts, lipoma and perineurioma.
The course of treatment for the peripheral nerve tumour depends on its type, whether it is symptomatic, and the extent of spread. If the tumour is small, grows slowly and doesn’t cause any symptoms, the physician may elect to just keep it under observation and monitor it regularly. Larger, fast growing tumours that cause symptoms need surgical intervention. The aim of the surgical intervention is to remove the entire tumour without damaging the adjoining healthy tissue or affecting nerve function. Depending on the location and size of the tumour, surgical removal could cause some neurological deficits. The advantages and disadvantages of the surgical approach will be weighed carefully by the physician before deciding on a course of action. The doctor may recommend stereotactic radiosurgery to remove the nerve tumour. In this procedure, the surgeon delivers gamma radiation in a targeted manner to the tumour without making an incision in the skin.
Spinal vascular malformations
Spinal vascular malformations are a relatively rare condition in the spine and spinal dura, in which abnormal connections are formed between the arteries and veins, forming a tangle where oxygenated and deoxygenated blood mix. Spinal vascular malformations, also called spinal arteriovenous malformations, deplete the surrounding tissue of oxygen and cause neurological damage. The various types of spinal vascular malformations are spinal dural arteriovenous fistulas, spinal arteriovenous malformations, juvenile arteriovenous malformations and pial spinal arteriovenous malformations.
The appropriate course of treatment depends on the type of malformation in question will be decided upon by the surgeon in charge of the case. Most cases are treated with surgical removal or embolization. Surgery usually involves resecting the tangle of vessels and connecting the arteries and veins back correctly. This can usually be achieved with fairly low risk to the patient, subject to its exact location in the spine. Embolization is an effective technique used to treat certain types of lesions. The procedure involves inserting a catheter into the lesions under fluoroscopy guidance, and injecting an embolising agent. The chemical closes the capillaries, like a glue, and stops blood supply to the lesion. This helps control blood loss during the surgery.
Spinal infections are rare, but occur in the spinal column, intravertebral discs or the vertebrae of the spine. These infections are usually bacterial in nature and are transported to the site of infection through the bloodstream. The infection can affect the structural integrity of the vertebrae if it progresses. The infection could cause an inflammation of the discs, causing discitis.
Spinal infections are typically treated with long-term intravenous antibiotic or anti-fungal therapies. The exact drug therapy is chosen after the organism causing the infection is identified. The drug therapy is typically administered for 6-8 weeks to rid the patient of the infection completely. If non-surgical interventions are ineffective, or if spinal stability is compromised, then surgery may be recommended. The goals of surgical interventions for spinal infections are to debride the infected tissue, restore blood flow to the affected area to promote healing, restore spinal stability and to limit the degree of neurological impairment.