Lumbar Microdiscectomy

What is a Lumbar Microdiscectomy?

Lumbar microdiscectomy is a minimally invasive spine surgery performed to relieve pressure on a spinal nerve caused by a herniated lumbar disc. The operation removes the portion of disc material that is compressing the nerve while preserving the surrounding muscles, joints, and spinal stability. It is the most commonly performed spine surgical procedure and is highly effective — relieving sciatica in more than 90% of appropriately selected patients.

The term microdiscectomy reflects both its key elements: 'micro' refers to the use of the microscope under high magnification — allowing precise, detailed visualisation through a very small incision; and 'discectomy' refers to the removal of the herniated disc material compressing the nerve.

At One Brain and Spine, our Melbourne neurosurgeons perform lumbar microdiscectomy using both microscopic techniques, tailored to the individual patient's anatomy, disc herniation characteristics, and clinical presentation.

Why is Lumbar Microdiscectomy Performed?

Microdiscectomy is performed to relieve the symptoms of nerve compression caused by a lumbar disc herniation. A disc herniation occurs when the inner gelatinous material of an intervertebral disc (the nucleus pulposus) protrudes through a tear in the outer fibrous ring (the annulus fibrosus), pressing against a spinal nerve root. This compression causes the characteristic symptoms of sciatica — radiating leg pain, numbness, tingling, and sometimes weakness.

Surgery is considered when:

• Leg pain (sciatica) persists despite appropriate non-surgical treatment for four to six weeks
• Progressive neurological deficit is present — particularly weakness in the leg or foot (foot drop)
• Cauda equina syndrome develops — bladder or bowel dysfunction from severe multi-level compression; this is a surgical emergency
• Severe, intractable pain cannot be controlled with high-dose analgesics

Most disc herniations (approximately 80–90%) will improve with conservative management over time and do not require surgery. Non-surgical options including physiotherapy, activity modification, and spinal injections are always considered before recommending surgery unless urgent neurological symptoms are present.

Who is a Candidate for Lumbar Microdiscectomy?

The ideal candidate for lumbar microdiscectomy is a patient with leg-dominant pain (sciatica), confirmed disc herniation on MRI at a level corresponding to the clinical symptoms, and persistent symptoms despite an adequate trial of conservative treatment. Patients with significant neurological deficit — particularly weakness — are prioritised for earlier surgical intervention. A careful clinical and radiological assessment is always performed before recommending surgery.

What Happens Before Surgery?

Preoperative Assessment

Prior to surgery, patients undergo a detailed clinical review including neurological examination, review of MRI imaging, and routine preoperative investigations (blood tests, ECG). The diagnosis and surgical plan are confirmed, and informed consent is obtained after a thorough discussion of the procedure, alternatives, and risks.

Preparing for Surgery

Patients fast from midnight before surgery. Regular medications are reviewed — blood thinners (including warfarin, Xarelto, Plavix, and aspirin) are typically ceased several days beforehand. Most patients are admitted on the morning of surgery. Arrangements should be made for a family member or friend to drive the patient home after discharge.

What Happens During Lumbar Microdiscectomy?

The procedure is performed under general anaesthesia with the patient positioned prone (face-down) on the operating table, allowing access to the lumbar spine. An intraoperative X-ray is used to precisely confirm the correct spinal level before the incision is made.

Through a small incision in the midline of the lower back — typically 2 to 3 centimetres in length — the spinal muscles are gently retracted using a tubular or sequential dilating system to minimise muscle disruption. A small window is then created in the lamina (the bony arch at the back of the spine), a technique called laminotomy, to expose the underlying ligamentum flavum. This ligament is carefully removed to reveal the compressed nerve root beneath.

Once the nerve root is identified, it is gently moved aside to expose the herniated disc material. The prolapsed disc fragment is then carefully removed using fine microsurgical instruments under high magnification. Decompression of the nerve root is confirmed, and the wound is closed with dissolvable sutures. The procedure typically takes 45 to 90 minutes depending on complexity.

Microscopic Microdiscectomy

The traditional and most widely performed technique. An operating microscope provides powerful illumination and magnification — typically 4 to 25 times — allowing the neurosurgeon to work with exceptional precision through a small incision. The microscope enables detailed visualisation of the nerve root, disc herniation, and surrounding structures, facilitating safe and thorough disc removal. One Brain and Spine's neurosurgeons are trained in advanced microsurgical technique and use the operating microscope routinely for microdiscectomy.

Anaesthesia and Hospital Stay

Lumbar microdiscectomy is usually performed under general anaesthesia. Most patients are hospitalised for one to two days following the microscopic technique with a small proportion discharged on the same day as surgery. For rare occasions when a patient is unable to tolerate a general anaesthetic due to age or other medical conditions a lumbar microdiscectomy may be performed under a spinal block.  Patients can walk and mobilise from the day of surgery.

Outcomes of Lumbar Microdiscectomy

Lumbar microdiscectomy has one of the highest success rates of any elective spinal procedure. When correctly indicated — leg-dominant sciatica from a confirmed disc herniation — more than 90% of patients achieve good-to-excellent relief of leg pain. The majority experience significant improvement within days of surgery.

Back pain responds less predictably than leg pain to microdiscectomy. The procedure is primarily designed to decompress the nerve, not to treat back pain. Some improvement in back pain may occur once the inflamed nerve is decompressed, but pre-existing chronic back pain should not be expected to resolve.

Neurological recovery — improvement in weakness, numbness, and tingling — occurs more gradually than pain relief and may take weeks to months. Weakness that has been present for more than several weeks before surgery may not fully recover even after technically successful nerve decompression.

Risks and Complications

Anaesthetic Risks

All general anaesthetics carry a small risk of medical complications including cardiac arrhythmia, chest infection, urinary tract infection, deep vein thrombosis (DVT), and pulmonary embolism. These risks are higher in patients with pre-existing medical conditions and are minimised by careful preoperative assessment and anaesthetic management. Your anaesthetist will discuss these risks with you prior to surgery.

General Surgical Risks

• Wound infection — approximately 1–2%; treated with antibiotics, and rarely requires surgical washout
• Bleeding — intraoperative or postoperative haematoma; rarely requires return to theatre
• CSF leak (dural tear) — occurs in approximately 1–3% of cases; usually managed conservatively with bed rest

Specific Risks of Microdiscectomy

• Recurrent disc herniation — the most common specific complication, occurring in 5–10% of patients. Most of the disc is left intact at surgery, allowing the remaining disc to re-herniate in the future. Recurrent herniation may be managed with repeat microdiscectomy; multiple recurrences may ultimately require spinal fusion.
• Nerve injury — injury to the nerve root causing persistent or worsening leg pain, numbness, or weakness; rare in experienced hands
• Bowel or bladder dysfunction — from nerve root injury; very rare
• Persistent symptoms — some patients have incomplete pain relief, particularly those with longstanding nerve compression or pre-existing nerve damage
• Requirement for further surgery — including fusion, if instability or recurrent herniation occurs

Alternatives to Surgery

Non-surgical management of lumbar disc herniation includes physiotherapy, activity modification, anti-inflammatory and neuropathic pain medications, and spinal injection therapy (epidural steroid injections or selective nerve root blocks). These are always considered before surgery and are effective for the majority of patients. Surgery is reserved for cases where conservative treatment has failed, or where urgent neurological indications are present.