Spine Surgery Paralysis Risk: How Technology Reduces It

Spine surgery paralysis risk is small: injury to the nerves or spinal cord is uncommon, yet paralysis is the complication patients fear most. Modern spine surgery reduces that risk with layered technology: neuromonitoring that warns the surgeon in real time, CT scanning inside the operating theatre, high-magnification microscopes, and navigation and robotic guidance that place each screw on a path planned in advance.

Dr. Puneet Girdhar, then Principal Director & Head, Ortho Spine, MIS & Robotic Spine Surgery at BLK-Max Super Speciality Hospital, New Delhi, India, framed his 2024 masterclass around exactly this fear. Safety in spine surgery, he said at the outset, is very important. The sections below explain how each layer works, what it protects against, and what Dr. Girdhar's own figures show. It is one part of the spinal surgery technology guide.

Can spine surgery cause paralysis?

Any operation near the spinal cord or nerve roots carries some risk of neurological injury, but serious injury is uncommon in elective spine surgery, and the purpose of modern safety technology is to make it rarer still. In Dr. Girdhar's experience, patients arrive with three fears: that the operation will paralyse them, that they will spend two to three months in bed, and the expense.

He answers the first fear with an analogy from aviation. Air travel is safer than car travel because of the technology built into it. Spine surgery has gone through the same transformation: over the past 20 years, technology has been added to almost every procedure. The risk has not disappeared; it has been engineered down, one layer at a time.

Intraoperative neuromonitoring: an early warning for the nerves

Intraoperative neuromonitoring is the continuous electrical testing of nerve function during surgery. Before the operation begins, electrodes are placed on the patient in the operating theatre. Throughout the procedure, small currents are passed and the responses recorded, so that every nerve can be followed on screen as an electrical trace. The aim, as Dr. Girdhar put it, is to check continuously that the surgeon is not doing anything that could harm the patient.

The monitoring he described includes two modalities:

• Electromyography (EMG), which records the electrical activity of muscles supplied by individual nerve roots. It is particularly sensitive to irritation of a nerve root, for example when a screw or instrument comes close to it.
• Motor evoked potentials (MEP), which test the motor pathway running through the spinal cord to the limbs. A fall in the signal can indicate that the spinal cord is under threat.

When a signal changes, the team can stop, reverse the last step or adjust the correction before an injury becomes permanent. This is why neuromonitoring matters most in deformity surgery, where the spine is straightened and the cord is under the greatest strain. All of Dr. Girdhar's deformity corrections are performed under neuromonitoring; in the revision case he showed, all the nerve signals were normal after surgery. The deformity cases themselves are described in severe spinal deformity surgery: curves beyond 90 degrees.

CT scanning inside the operating theatre

BLK-Max has a 3D CT scanner in the operating theatre itself. A CT scan is taken with the patient already positioned on the operating table, which serves two purposes. First, it provides the images on which robotic or navigated screw paths are planned, reflecting the patient's anatomy in the exact position for surgery. Second, it allows the position of implants to be checked before the operation ends, so that a misplaced screw can be corrected in the same sitting rather than discovered on a scan days later.

Magnification and light: the operating microscope

The operating microscope gives the surgeon magnification of five, six or ten times, with strong illumination of a small, deep field. Dr. Girdhar presented it as a tool for safe spine surgery. In practical terms, better visualisation lets the surgeon distinguish the nerve, the protective membrane around it and the disc or bone pressing on it, and work between them with less traction on the nerve. The microscope is also what makes tubular surgery possible: an entire decompression can be performed through a small tube, as described in endoscopic spine surgery for slipped disc and stenosis.

Navigation and robotics: putting each screw where it was planned

Many spinal operations fix vertebrae together with pedicle screws, which pass through a narrow column of bone (the pedicle) into the body of the vertebra. A misplaced screw can breach the pedicle and touch a nerve root. Navigation and robotics exist to prevent that.

Dr. Girdhar showed the robotic workflow step by step:

1. Imaging. The 3D CT scan is taken in theatre.
2. Planning. The surgeon plans the path of each screw on screen.
3. Positioning. The robotic arm moves into the planned position over the spine.
4. Drilling. Through a small incision, the surgeon drills along the guide held by the robotic arm.
5. Live imaging. The position is followed on screen as the screw goes in.
6. Verification. The planned screw (shown in blue) is overlaid on the final screw (shown in yellow). Where they match, the screw is where it was intended to be.

In the case he presented, the blue and yellow images matched at every level, including the S1 screw at the base of the spine, with the planned size and length confirmed.

His accuracy figures were stark: about 93% without a robot and 100% with it. Published comparisons generally report higher accuracy for robot-assisted placement than for freehand technique, although no method is entirely free of error. Dr. Girdhar also cited less blood loss, a shorter hospital stay and patients walking the day after spinal fixation.

The robot extends beyond screws. In another case, a disc was removed and replaced with an interbody cage, a spacer placed in the disc space to restore its height and allow the vertebrae to fuse. The cage position was planned on the robot, inserted, and then expanded to restore the height of the disc space. The whole operation, disc exchange and fixation, was done through two small incisions. His 2025 masterclass revisited robotics in more depth, in how robotic spine surgery works.

Ultrasonic bone cutting

For the largest reconstructions, Dr. Girdhar uses ultrasonic bone cutting. An ultrasonic bone scalpel cuts bone with high-frequency vibration and is less likely than a conventional drill or saw to damage the soft tissues around it, which matters when the cut lies millimetres from the spinal cord. He used it in a 16-hour reconstruction for a severe congenital deformity, where bone had to be removed safely.

What "100% safe" means in practice

Dr. Girdhar's message was that this technology helps make spine surgery 100% safe. The claim describes an aim and the direction of travel rather than a guarantee: no operation on the spine is free of risk. What the technology does is remove specific, well-understood sources of harm. Neuromonitoring catches nerve compromise while it is still reversible. Intraoperative CT catches a misplaced implant before the patient leaves theatre. The microscope and endoscope reduce damage to surrounding tissue. The robot reduces variability in screw placement.

For patients and referring doctors, this suggests practical questions to ask before surgery:

• Will the operation be performed under neuromonitoring, and which modalities will be used?
• Is imaging available in theatre to confirm implant position before the operation ends?
• Will the procedure be done through a minimally invasive approach, and if not, why not?
• For fusion, will screws be placed with navigation or robotic guidance?

A wider discussion of spine surgery risk, from another surgeon in the Jivo Masterclass series, is in making spine surgery 99% safe.

Do patients spend months in bed after spine surgery?

Safety technology also dissolves the second fear. Because the operations are done through small incisions with less blood loss, recovery is measured in days. According to Dr. Girdhar, about 90% of spinal surgeries are now minimally invasive, with discharge in about a day, and even after a fusion his patients walk on the day of surgery. The two to three months in bed that patients expect belong to an earlier generation of spine surgery; his full fusion recovery timeline is in endoscopic spine surgery for slipped disc and stenosis.

The audience questions from this session, including Dr. Girdhar's answers on fusion recovery, are on the Live Discussion page. Costs for fixation procedures are listed on the spinal decompression and fixation cost page.