What are the risks of hernia surgery?

The risks of hernia surgery depend on its location , the technique used or special circumstances .

Cervical hernia 

A hernia of cervical location affects nerve roots that originate from the spinal cord or the spinal cord itself, so its manipulation may risk damaging them and cause serious neurological sequelae such as paresis, paralysis or paraplegia. Logically, the experience of the surgeon makes these risks are minimized. They are usually approached from the front by resecting the disc and hernia . In general, the disc is replaced by a prosthesis or fixation is made by means of interbody cages, associated or not with plates screwed to the vertebrae. The posterior route has occasional indications. The proximity of the recurrent nerve that supplies the vocal cords in the anterior approach makes it possible to injure it with aphonia as a sequel.

The involvement of the nearby large vessels is exceptional, such as perforation of the esophagus, a very serious complication due to the risk of infection of the mediastinum ( mediastinitis ).

There are percutaneous techniques aided by X-rays to reach the disc with a needle or trocar and inject substances that destroy the hernia (chemical discolysis) or by energies such as radiofrequency or laser   ( discoplasties ) or mechanical aspiration. They have their particular indications, although the intervened disc remains altered in its biomechanical function and in the long run predisposes to degenerative changes. As is understood, these techniques reduce surgical risk by being less aggressive.

Thoracic or dorsal hernia

In the exceptional hernias of the thoracic or dorsal area, the risk of paraplegia is very high if they are approached posteriorly, through the spinal canal, due to possible vascular damage with ischemia of the cord. For this reason, they are approached posterolaterally by resecting a portion of a rib or through an anterior thoracotomy between the ribs.

More modernly, video-assisted thoracoscopy surgery is performed. It is done through small portals through the thorax by endoscope vision after deflating the lung. Instruments designed for this purpose are used and with the advantage of direct vision on a TV monitor of the vertebrae. As in cervical hernias, the hernia can also be “dissolved” by percutaneous technique with the introduction of a needle into the disc guided by X-rays and the application of the same techniques as in the cervical area. The frequent calcification of these hernias limits their application due to ineffectiveness in these cases.

Lumbar hernia

Lumbar hernias are technically less risky at the time of surgery, since the cord ends in the area of ​​the first lumbar vertebra and the injury would be limited to one root, the one affected by the hernia, except in the case of the syndrome of the horse tail. The sequels would be limited to the functions or territories dependent on it. The risks in the medium and long term are postsurgical fibrosis or residual instability .

The first is due to the formation of a scar around the nerve root that "strangles" it, causing the same symptoms as a herniated disc. The second is due to the loss of function of the disc that causes abnormal mobility that can irritate the root or cause chronic low back pain. Its treatment would be the fixation or arthrodesis of the affected segment.

Post-surgery complications

All these techniques for treating hernias of any location as they are close to the dura that surrounds the nerve structures and contains the cerebrospinal fluid, in which the nervous system “swims”, has the risk of tearing it, creating leaks of this fluid causing severe post-surgical headaches or fistulas that are difficult to treat. They can even be the origin of infection meningitis. There are hernias that enter the thecal space (inside the dura mater) and when they are removed, it tears and creates a fistula .

Post-surgery disc infection, although rare, is serious and causes significant pain. It usually responds well to antibiotic treatment and immobilization. Injuries to nearby vessels can cause bleeding that can damage the nerve root or spinal cord but is rare. Sometimes the neurological deterioration caused by the hernia is not reversible as in chronic cases and leaves motor sequelae, sensory or chronic pain.