The chances of a successful conservative therapy in case of recurrent disk herniations are lower as compared to primary disk herniations.

This can be explained by the fact that the neural structures are less “mobile” in the spinal canal due to adhesions or scar tissue without the possibility to “give way.” On the other hand, it was shown that a high percentage of the recurrent disk herniations include endplate disk material, with harder consistency and less ability to shrink than “pure” nucleus material [14].

Indication for surgery as well as the choice for different types of surgical techniques follows the clinical symptoms of the patient.

If signs of nerve root compression are paramount, the primary surgical option is the decompression/re-diskectomy. Unless functional factors such as gross instability or leading back pain are predominant, there is no need to consider additional stabilization.

The options for surgical treatment range from endoscopic or microsurgical re-sequestrectomy/diskectomy to a fusion/reconstruction procedure. Besides the natural process of degeneration of the functional spinal unit, the technique of the previous surgery plays an important role regarding a segmental instability with consecutive narrowing of the spinal canal. Laminectomy, extensive resection of the facet joint and iatrogenic discontinuation of the pars interarticularis are predictable factors of a postoperative segmental instability [15, 16]. In other words minimally invasive techniques like endoscopic or microsurgical procedures are able to prevent postoperative instability due to less resection of bony structures [17]. Therefore the surgeon has the option for minimally invasive techniques in revision surgery as well.

In the setting of a clinically dominant sciatica, the solitary revision of the spinal canal is indicated, irrespective of the type of a previous surgery. If the pathology leading to nerve root compression is caused by a segmental instability, additional reconstruction of the functional spinal unit for the purpose of spinal fusion is necessary. Most of the time, the patients report also significant back pain.

Up to now there is a lack of clear algorithms regarding the treatment of recurrent disk herniations. A survey among neurological and orthopedic spine surgeons in the USA concerning the surgical treatment patterns of one- and two-time recurrent lumbar disk herniations revealed significantly different opinions. The surgical treatment options were revision microdiskectomy, revision microdiskectomy with in situ fusion, posterolateral fusion using pedicle screws, and PLIF/TLIF or ALIF procedures in combination with posterior instrumentation. Experienced surgeons with more than 15 years of practice were more likely to select just microdiskectomy in contrast to surgeons with fewer years who were more likely to select the microdiskectomy in combination with PLIF/TLIF. Overall, the probability that two randomly selected spine surgeons would disagree on the surgical procedure of two-time recurrent disk herniation was 69 % [18].

The previous surgical technique influences the revision surgery strategy. In contrast to the first operation, the surgeon is faced with scar tissue and altered anatomical landmarks in terms of bony defects. In principle all operative techniques (endoscopic, microsurgical, and macrosurgical with and without fusion procedures) are also evaluated in revision surgery. The selection of the appropriate technique should be adapted to the surgeon’s experience. The steps of microsurgical re-diskectomy/re-decompression will be described.

The exact localization of the recurrent disk herniation should be known as well as its topographic relation to the nerve root and/or scar tissue. This can be best achieved with an MRI with contrast media. The bony landmarks (e.g., medial facet border, lamina border, isthmus) can be seen on the x-rays. If necessary a CT scan can give detailed information about the extension of the previous laminotomy, hemilaminectomy, facetectomy, etc. It also provides data concerning potential ossification of the herniated disk (Fig. 19.4).

The disk space height is localized under fluoroscopic control and a 2 cm skin incision is placed centered over the disk space or over the maximum extension of the recurrence. Sharp subperiostal dissection is done preferably from the remaining superior lamina down to the transition zone of the superior lamina and the inferior facet. The reliable exposure of the bony “edges” is essential. The scar tissue must be safely detached from the bony rim of the lamina and the medial border of the inferior facet. Extreme care has to be taken if MRI shows a bulging dura dorsal to the lamina border. With a small blunt dissector or a diamond drill, the caudal border of the superior lamina is undercut until untouched ligamentum flavum or healthy dura is exposed under the lamina. Once healthy dura is identified, dissection of the scar tissue is started along the medial border of the inferior facet until the rim of the superior facet is identified.

Blunt dissection is performed between bone and scar tissue until the exposure of the lateral border of the exiting nerve root is achieved. This is followed by the decompression along the shoulder of the nerve root until the caudal pedicle. If significant fibrosis is found, a layer of scar tissue may be left on the nerve root, respectively, on the dural sac to avoid dural tear.

The exposure of the lateral dural margin, respectively, of the lateral nerve root margin is followed by a careful mobilization of the nerve root to the middle. There are often adherences of the nerve with the disk space. In these cases it is advisable to leave the nerve in place and open the scar tissue lateral to the nerve to get a safe access to the recurrent herniation. The herniated disk can then be mobilized carefully with a blunt dissector or with a small nerve hook.

At the end of the operation, the neural structures, especially the dura, are checked again for integrity and sufficient decompression. Careful hemostasis and irrigation of the approach and the epidural space finalize the intervention. A drainage is not needed in most of the cases; the patients are allowed to stand up immediately after they regained circulatory stability and consciousness. If there may be high risk for a recurrent disk herniation, the use of a soft brace for 4–6 weeks postoperatively is advised.