Spinal Surgery

The system works as follows: just as satellites detect the position of a GPS unit in our car and the navigation system displays its location on current maps, a camera in the operating room tracks the position of surgical instruments. This position is displayed on the system’s screen, always in real time, in direct correlation with the patient’s actual anatomy (optical tracking technology).

In place of the camera, the system can use a transmitter. The transmitter generates an electromagnetic field around the patient, and anything that enters this field is automatically detected (electromagnetic tracking technology). Tiny sensors attached to the surgeon’s instruments are recognized within the field and provide continuous, highly accurate information about the position of the tools in relation to the patient’s anatomy.

Surgical navigation systems are located in the operating theater and use either optical or electromagnetic tracking technology. They consist of the specialized camera or transmitter, the computing unit with its dedicated software, the display monitor, special navigation instruments, and adaptors that allow standard surgical tools to be recognized by the system.

The camera or transmitter identifies and tracks the position of moving instruments by cross-referencing the corresponding signals (sphere reflection in optical technology, signal coordinates in electromagnetic technology). The computing unit processes these signals, and their position is projected onto the system’s display. At this stage, the “map” is no longer a road atlas but instead a CT or MRI scan—or even a fusion of multiple imaging studies—providing surgeons with unparalleled precision during surgery.

Modern surgical navigation systems provide an integrated methodology that includes imaging examinations (MRI, CT, MR angiography, CT angiography, ultrasound), preoperative planning, intraoperative navigation, and postoperative data archiving. Surgical navigation is primarily used in Neurosurgery, Orthopedics, and Otolaryngology.

Advances in surgical navigation technology have significantly contributed to the progress of Neurosurgery and are now internationally established as the method of choice for cranial procedures, replacing older frame-based stereotactic techniques.

The main applications in neurosurgery include:

• Removal of brain and spinal cord tumors (selection of craniotomy site, surgical trajectory and approach, tumor localization and delineation).
• Biopsy and catheter placement.
• Functional Neurosurgery (placement of electrodes for deep brain stimulation).
• Spinal Surgery

Navigation has rapidly expanded in recent years for spine procedures, as it provides intraoperative three-dimensional visualization of anatomy and enables precise localization of instruments and implants (e.g., screws) relative to the patient’s anatomy. This allows for detailed planning of the surgical approach and real-time visualization of screw placement.

Additionally, intraoperative navigation has recently been applied in musculoskeletal tumor surgery. We have used navigation in several cases for percutaneous ablation of osteoid osteomas or metastatic lesions, often combined with osteoplasty.

This information ultimately offers:

• Greater accuracy and effectiveness of surgery: For example, in procedures involving the placement of screws in the cervical vertebrae during posterior scoliosis surgery, cases using navigation showed a significant reduction in misplacement rates—1.8% compared to 11% in cases using only radiographic devices.
• Reduced operative time: In open posterior lumbar fusion surgeries, cases using intraoperative navigation had an average reduction of 40 minutes compared to those relying solely on radiographic devices.
• Lower radiation exposure during spinal procedures: In the placement of transpedicular screws, navigation reduced radiation exposure by 70% (from 11.5 seconds per two screws per vertebral level using only radiographic devices to 3.5 seconds with navigation).
• Enhanced surgeon confidence: Surgical navigation can confirm the surgeon’s judgment and decisions, which previously relied solely on anatomical knowledge.
• Shorter patient hospital stays.

Specifically for spinal procedures, the O-arm system allows the surgeon to visualize complex, often unpredictable spinal anatomy in three dimensions in real time. This reduces technical difficulties, allowing the most challenging and time-consuming parts of surgery to be accurately anticipated and potentially reducing overall operative time by up to one-third. Consequently, high-risk patients can now undergo safer procedures, with lower morbidity.

Due to the complete anatomical visualization, no vertebrae are skipped because of challenging anatomy, and there is no need for less effective techniques. This ensures that all vertebrae are included in the fusion with screws, resulting in excellent outcomes for patients.

Moreover, patient concerns about postoperative paralysis are greatly alleviated. By reducing operative time and minimizing risk to neural tissue, surgical navigation allows for shorter anesthesia duration, less blood loss, fewer transfusions, lower infection risk, shorter ICU stays, and overall reduced patient stress, leading to a significant decrease in non-surgical morbidity.

For the first time in Greece, in 2016, the Metropolitan Hospital successfully implemented a 3D imaging and surgical navigation system for children with scoliosis.

The system enabled real-time placement of implants with CT-level accuracy. This precision virtually eliminates the risk of medical errors and permanent neurological damage, while also providing excellent aesthetic outcomes—particularly important for girls with scoliosis. The system is now used for both pediatric and adult patients with scoliosis or kyphosis.

Scoliosis and Kyphosis

The human spine has natural curves that help the body stand upright and remain flexible. Scoliosis is characterized by a twisting of the spine. It affects children, adolescents, and adults of both sexes. Idiopathic scoliosis is the most common form, affecting approximately 2% of the global population. Fortunately, only a small percentage of these cases require treatment. Kyphosis is an increase in the natural thoracic curve or a decrease in the normal lumbar curve. It usually affects older adults with osteoporosis, but adolescents can also be affected.

Causes

In most cases, the cause of scoliosis in children and adolescents is unknown, although it is believed to have a genetic background passed down through generations. Kyphosis in adolescents is often caused by Scheuermann’s disease, which can lead to pain. Adult scoliosis usually results from untreated childhood or adolescent scoliosis or from spinal aging. In adults, kyphosis is typically age-related, causing pain and difficulty in maintaining an upright posture.

Symptoms:

Parents may suspect scoliosis in a child or adolescent if one shoulder appears higher than the other or the pelvis seems tilted. Look for back deformities, usually in the shape of an “S” or “C.”

In adolescents with back pain and kyphosis, Scheuermann’s disease should be ruled out. In adults, a lateral shift of the body to the right or left may indicate scoliosis, especially if accompanied by pain.

Kyphosis is noticeable from the progressive “hunchback” appearance and the need to walk with bent knees. Pain is almost always present. Each child or adult with scoliosis or kyphosis is a unique case, and treatment must be individualized.

Monitoring

Children and adolescents with mild scoliosis or kyphosis should be regularly monitored for potential progression as their body grows. Adults should be monitored if scoliosis or kyphosis is present but not associated with neurological problems. In the early stages, targeted physiotherapy and medication play a key role in reducing pain.

Bracing

For children and adolescents with moderate scoliosis, advances in materials have led to lighter and more “aesthetic” braces that are more easily accepted. Classic Boston braces, as well as newer dynamic or nighttime Providence braces, can be used depending on age, scoliosis type, and severity. Unfortunately, no type of brace can correct scoliosis in children or adolescents; their role is limited to halting curve progression. In adolescents with Scheuermann’s disease, braces may help halt progression, manage pain, and correct kyphosis. In adults, braces are less effective than in children.

Surgical Alternatives

For children and adolescents, surgical correction of scoliosis is recommended for curves exceeding 45 degrees. Without surgery, these curves may continue to worsen even after skeletal maturity, leading to chronic pain, respiratory dysfunction, and psychosocial effects, especially in girls. Once scoliosis exceeds 45 degrees, braces are no longer effective. For adolescents with Scheuermann’s kyphosis, surgery is indicated if the curve progresses to 70 degrees despite bracing and is associated with pain.

In adults, treatment is generally surgical. Minimally invasive procedures Advantages of Intraopecan help correct kyphosis and relieve pain from osteoporotic fractures. Adult scoliosis should be surgically corrected if associated with pain in the lower back or legs that limits daily activities and reduces quality of life.