Advancements In Minimally Invasive Spine Surgery

Minimally Invasive Spine Surgery (MISS) has seen a lot of advancement in recent years.  Originally, minimally invasive techniques were used for simple procedures like percutaneous fixations for spinal fractures or disc decompression. With technological advancements, minimally invasive techniques have now expanded their horizon to tumour excisions, addressing spinal canal stenosis, stabilising unstable degenerative spines, or even treating spinal infections. The advent of navigation and O-arm technology has further refined MISS to be more refined. 

Minimally Invasive Approach in Spine Care:

Minimally invasive techniques can be performed using posterior interlaminar or transforaminal approaches.  They can also be used in anterior approaches where a direct anterior transperitoneal approach through a micro-incision is performed, or in lateral approaches such as lateral lumbar interbody fusion (LLIF) or extreme lateral interbody fusion (XLIF). These techniques allow for not only decompression but also debridement, abscess drainage, stabilisation of unstable spinal segments, and tumour excision. 

For interbody fusion, the fusion rate for anterior LLIF is around 90 per cent, which is comparable to posterior minimally invasive techniques like MIS TLIF (transforaminal lumbar interbody fusion). However, complications may be slightly higher due to anatomical differences. In some cases, there may be incomplete decompression due to the dependence on indirect decompression – this can be managed by placing a large cage in the interbody space to widen the foramen and relieve nerve root pressure.

Advancements in techniques for approaching the anterior spine through laparoscopic transperitoneal methods or thoracoscopy have further benefited spine surgery. The introduction of robotic spine surgery, in combination with navigation, and augmented reality (AR), is also making notable contributions. 

Foundations of Minimally Invasive Spine Surgery: 

The early foundation for minimally invasive spine surgery was laid with the use of microscopes which enhanced magnification and visual clarity during surgery, reducing errors.  This was followed by the development of tubular retractors, allowing the use of microscopes for better visualisation during procedures like discectomy or spinal canal decompression. Eventually, endoscopes were developed, integrating magnification and offering saline irrigation and suction capabilities. 

Applications of Endoscopes and Tubes:

Unlike traditional microscopes, endoscopes allow for a broader field of vision, with an adjustable angle of 30-60 degrees. Endoscopes are commonly used for posterior interlaminar and transforaminal approaches, while tubes remain the mainstay for anterior and lateral approaches. Through small incisions, tubes allow for soft tissue retraction, decompression, and preparation of bone for cage placement.

Role of Navigation in Improving Precision:

The use of navigation has improved the precision of implant placement and tumour resection, particularly in cases where the anatomy is distorted. While navigation has not significantly impacted decompression procedures, it is invaluable for hardware placement, especially in cases of abnormal or deformed spines.

Robotics and Augmented Reality in Spine Surgery:

Robotic surgery in spine surgery is gaining attention, though its primary benefit lies in the precision of implant placement. It can also be used in anterior spinal releases or tumour excisions, such as in sacrectomies. Although the true benefits of robotics are not fully established, the trend is shifting toward its use in spinal surgeries. Augmented reality is another emerging technology in spine care, helping to reduce X-ray exposure and enhance precision, particularly in screw placement. Some studies suggest that AR may further improve the accuracy of implant positioning in spine surgeries.

Advantages of Minimally Invasive Surgery:

As for benefits, MISS minimises tissue damage and approach-related complications in spine surgery. It leads to lesser scar tissue formation and fewer destabilising effects from a wider surgical approach. MISS is also associated with less blood loss, reduced surgical time, shortened hospital stays, and earlier return to work. Overall, MISS techniques are as effective as standard open techniques in terms of surgical outcomes, neurological recovery, and spine stabilisation with added advantages of lesser approach-related complications.

Dr. Amrithlal. A. Mascarenhas

Guest Author Consultant - Spine Surgery, Manipal Hospital Millers Road, Bengaluru