Abstract
Introduction
The XLIF (extreme lateral interbody fusion) was introduced in 2001. It is useful as an alternative to ALIF approach especially in obese patients or in case of repeat surgeries to avoid vascular complications. This minimally invasive spine surgery allows to place big foot print implants, minimizing their subsidence and allows even to correct severe deformities. On the other side it is sophisticated, requires special instruments and neuromonitoring. One of the biggest disadvantages is a neurological deficit caused by the transpsoas access, despite of neuromonitoring. The incidence of mostly transient weakness and numbness reaches in the reports from 0,6 to 33%. The goal of this study was to estimate, if most of the reports were enthusiastic in terms of persistent deficits and if it is possible for a skilled surgeon to learn it in relatively short time.
Material and Methods
40 patients (23 men and 23 women) in age of 25- 86 years (mean 63) underwent XLIF surgeries from march 2014 to august 2015 in our institution. All of them had neuromonitoring intraoperatively. Demographic data of the patients, indications, Op time, blood loss, outcome concerning neurological deficits and early complications were analyzed. The patients with deficit had at least 12 months follow up. We checked, if the surgery time becomes shorter, the more experience is present (4 skilled surgeons performed the procedures) and if deficits occur in the beginning of the learning curve.
Results
Most surgeries were monosegmental (37). Operated levels: L4/5: 26, L3/4: 9, L2/3: 5, L1/2: 3. Follow- up time was between 1 to 18 months (mean 7). Indications: instability: 15, degenerative: 13, discitis: 6, fractures: 4, deformity: 2. The Op time ranged from 37 to 134 minutes (mean76). In all patients the blood loss was not higher than 150 ml. 5 patients developed postoperatively motor neurological deficit. In 2 cases it was persistent (follow up time 13 and 12 months). The others were transient and resolved after 3 months. There were primarily 2 malpositions of implants (introduced into vertebral body of L 5 due to the angle of insertion), which leaded to 1 revision surgery. Persistent deficits occurred in 6. and 10. operated patients in the list, the transient in 18., 24. and 32. patient. 2 surgeries had to be abandoned due to the anatomical situation to avoid the iatrogenic nerve root damage.
Conclusion
The study shows, that even despite of correct neuromonitoring, neurological deficits can appear in XLIF approach. This complication seems to be dependent to the time of the retraction of the prevertebral structures. The longer the OP time (persistent weakness was associated with OP time longer than 120 minutes), the hazard of neurological arises (in transient ones Op times respectively: 58, 73 and 82 minutes). New technologies create often reluctance for many surgeons to accept it, as the learning curve may be long and complications rate high. After 4 surgeries the duration of the procedure was reduced at 35%. Compared with the data in the literature in own series, the neurological deficits were not higher and the learning curve relatively short. The accuracy of the approach (respecting the endplates space to avoid malpositioning) and the OP time has to be respected to avoid a nerve root damage. Reduction maneuvres and more manipulation may arise the ratio of complications. A skilled surgeon should be able to start performing the XLIF access without high rate of complications and become familiar with it after 4–5- surgeries.