Reasons for repeated surgical interventions in patients after surgery for spinal disc herniation

Background. The article presents a retrospective analysis of the causes of negative results of surgical treatment in elderly people with spinal disc herniation. The purpose of the work is to determine the causes of negative results of surgical treatment of disc herniation in the elderly and old patients compared with young patients, which will allow choose the correct surgical tactics in the future and prevent the complications. Materials and methods. A retrospective analysis of the surgical treatment of spinal disc herniation in 170 patients was carried out. The group of young people consisted of 92 patients, the group of elderly and senile age (60 years and older) included 78 patients. The first operation for disc herniation was performed from 3 months to 7 years before investigation in various medical institutions of Ukraine. Results. The disc herniation at the same level recurred in 61 % of young patients and almost 4 times less (14.1 %) in older ones. Disc herniation at an adjacent level is also found more often in young patients (10 %) than in the older age group (3.8 %). The authors attribute this fact to the more expressive disc dehydration with age, and the height of the interbody space is significantly reduced, while in young people the volume of the disc material significantly increases the risk of new sequestration. Conclusions. The results of this work indicate that the reasons for repeated surgical interventions for disc herniation depend on the age of a patient. A common cause of repeated surgical interventions in older patients is instability at the operated and adjacent levels, encouraging surgeons to more widely use stabilizing surgical interventions and more detailed preoperative planning for choosing a level of stabilization; in the older age category, stenosis prevails, therefore it is necessary to apply a wider decompression.


Introduction
Treating elderly and old people for spine pathologies becomes ever more vital every decade due to the demographic processes at play in our modern society; and this problems gains not only medical, but social and ethic dimensions [1,2]. Its essence lies in the difficulty of adequate evaluation, differential diagnostic of natural involutionary changes, as well as in choosing optimum treatment tactic for every individual patient [3][4][5][6]. Moreover, the surgery risk in this age group is much higher than in the younger one, which is why experts argue as to the best treatment options [7][8][9].
Among these patients, there is a recent rise in popularity of percutaneous treatments, such as epidural angiolysis, epidural steroid injections, percutaneous nucleotomy, Stryker-decompresor, laser discectomy etc. However, there is no consensus as to the useful-Bol', sustavy, pozvonočnik, ISSN 2224-1507 (print), ISSN 2307-1133 (online) Практична медицина / Practical Medicine ness of these treatments for the elderly and old patients, and the long-term outcomes are not always satisfying.
In order to understand the range of problems bringing about negative surgical outcomes among the elderly and old patients, we performed a retrospective analysis of repeated surgical interventions among the population who has already undergone operations of herniated intervertebral discs and compared causes of negative primary surgical outcomes among the young and older The purpose of the study is to determine the causes of negative outcomes of herniated intervertebral disc surgical interventions among the elderly and old patients compared with young patients. It helps choosing correct surgical tactics and preventing future occurrence of complications.

Materials and methods
Objects of research are the patients who have undergone herniated intervertebral disc surgical interventions at the lumbar spine.
Materials of the study were the reports of 170 patients having a history of herniated intervertebral disc operations at the lumbar spine who have undergone a repeated surgical intervention. Those patients had various degenerative clinical lumbar conditions. All the patients were operated at the Regional Orthopedic, Traumatology and Vertebrology Center "Rivne Regional Clinical Hospital" municipal institution from 2000 to 2018. All the patients had a history of herniated intervertebral disc surgical interventions at various medical institutions of Ukraine, 3 months to 7 years prior to the research. People of older age group (60 years and over) amounted to 78 (45.8 %) while those of younger age group (18-59 years) -to 92 (54.2 %) ( Table 1).
The majority of young (70.6 %) and older (53.8 %) patients had a history of microdiscectomy. Microdiscectomy with a stabilization of injured segment was performed in 11.9 % of young and 10.3 % of elderly and old people; wide decompression with a massive removal of posterior structures (pedicle, zygapophysial joints) and discectomy was performed in 6.6 % of young and 11.5 % of elderly and old people. 10.9 % of young and 24.4 % of older people had a wide decompression and posterior stabilization. (Table 2).
Patients were admitted with various complaints, namely a recurring herniated intervertebral disc at the same level, herniated intervertebral disc at the adjacent level, spinal locomotor segme4nt instability at the operated or adjacent level, epidural fibrosis with spinal canal stenosis, degenerative central and\or foraminal stenosis, metal construction failure, degenerative scoliosis.
Reasons for a repeated surgical intervention are presented in Table 3.

Results and discussion
At the operated level, recurring herniated intervertebral disc was found in 61% of younger patients and 4 times as rarely (14.1 %) in the older ones. At the adjacent level, recurring herniated intervertebral disc was also more prevalent among the younger patients (10 %) than in the older ones (3.8 %). This occurrence may be explained by the advancing dehydration of intervertebral disc and significant reduction of interbody space height. Young people have greater volumes of disc matter resulting in new sequesters.  Wide decompression (hemi-, laminectomy, facetectomy) + discectomy 6 (6.6 %) 9 (11.5 %) Wide decompression (hemi-, laminectomy, facetectomy) + discectomy + posterior autometal-spondylosis 10 (10.9 %) 19 (24.4 %) Degenerative scoliosis was observed in 3.8 % of older patients and no younger ones; instability at the operated level was observed twice as often in the older patients (30.8 %) than in the younger ones (13 %) while instability at the adjacent level was observed 5 times as often in the older patients (15.4 %) than in the younger ones (3.2 %). We might explain it by the fact that with advancing age degenerative changes affect all the spinal segments while in the younger people they are localized in the anterior locomotor complex.
Metal construction failure in the older population was mainly due to lysis around the screws (3.8 %) than to a break-down, while in the younger one -mainly to a break-down (4.2 %). It might be associated with a worse bone quality of older patients.

Conclusions
1. The most common reason for repeated intervention in older patients is instability at the operated and adjacent levels. It encourages surgeons to use stabilizing intervention more often and resort to a detailed planning as to a stabilization level. Older patients suffer from stenosis more often that the younger ones, thus requiring a wider decompression.
2. To prevent the epidural fibrosis, it is necessary to use non-invasive surgical procedures with a minimum intra-surgical blood loss. Besides a discectomy, older patients often require a degenerative deformation correction.
3. In case of a severe osteoporosis, to prevent the metal construction failure, surgeons should use special cement-augmented implants to improve the "implant-bone" contact. Degenerative scoliosis -3 (3.8 %) Fig. 1. X-rays after the primary intervention (a, b) and after a repeated intervention at L 4 -L 5

Практична медицина / Practical Medicine
Prospects of further development in the field. The obtained results enable a future development of differentiated intervention algorithm for herniated intervertebral discs in elderly and old patients taking into account various clinical conditions.

Conflicts of interests.
Authors declare the absence of any conflicts of interests that might be construed to influence the results or interpretation of their manuscript.