A minimal soft tissue damage approach of spondylolysis repair in athletes: preliminary report

Both spondylolysis and spondylolisthesis comes in second place in the causes of pain among athletes [14]. This problem is particularly marked in sports where there are repetitive movements of rotation and hyperextension of the lumbar spine [13]. Treatment options include both conservative management (reduction of activity, splinting, rehabilitation) and different operative methods of healing with damaged pars interarticularis [4, 13]. In 1970, Buck developed a method of direct repair of damaged pars with the use of screws placed on the lower edge of the lamina through the defect and moved upward, in the direction of the upper facet joint. This original method was carried out by open tissue preparation [1]. Its efficacy, in the treatment of spondylolysis, is more than 90% in both athletes and in people not practicing sport. Spondylolysis occurs more frequently in two groups: adolescents and athletes [3]. These are groups where the priority is to protect tissues from perioperative damage. We therefore present our modification of the Buck’s method, which we believe offers maximum protection of tissues by the use of minimally invasive techniques and the use of implants optimally matched to the diameter of the pars interarticularis.

We obtained approval for this study from an ethics committee of Poznan University of Medical Sciences. To date, eight pars defects in five patients were treated with the proposed method. All were males who professionally practice soccer. The age range was 13–18 years. In three cases, spondylolysis occurred unilaterally, on one level. In one case, spondylolysis had occurred on both sides on two levels. In one case, spondylolysis occurred on both sides on one level. Optimum screw location was achieved in all cases, i.e. passing from the base of the lower facet to the top of the upper facet without piercing the cortical bone. Pain levels in the first postoperative day were 2–3 on the visual analogue scale (VAS). All the patients were discharged on the first postoperative day. During the first postoperative week, the level of pain in all patients was 0 on VAS. There were no complications. All patients, after a 6 weeks period of immobilization in TLSO and 6-week rehabilitation, returned to sport at the previous level, while remaining completely free from pain and without functional deficits. Because the pain occurred only during intense physical activity, as it was mentioned at the beginning, ODI questionnaire was not applied, due to the lack of evaluation of this type of situation.

Spondylolysis occurs in 6% of the population. The occurrence amongst athletes is much greater, averaging 15% [2, 5, 10]. Non-surgical treatment is effective in almost 90% of people practicing sport professionally or competitively [6]. In others, especially professional athletes, pain associated with spondylolysis can significantly interfere with the achievement of appropriate results. There are currently several methods of obtaining fusion in spondylolysis, without fusing the entire motion segment [3, 7‐9, 11]. In comparison with these methods, especially in the population of athletes, Buck’s method is characterized by the highest efficiency [4]. The greatest disadvantage of this method is the need for muscle dissection from the lamina to the facet joint [1]. This causes considerable tissue damage which, combined with a scar generated in the subcutaneous tissues, may limit the optimum functionality of the back muscles. This is particularly undesirable in professional athletes, where even the slightest change in the functionality of tissues may affect the results achieved in sport. For this reason, methods of treatment, which achieve the effects obtained by the Buck method, but which spare tissue through the use of minimally invasive access, have been developed. These use the cannulated screw insertion path as recommended by Buck, after inserting the guide wire [15, 16]. The use of screws with a diameter of 4 or 4.5 mm is described in this methods [15, 16], but according to our measurements, obtained from the preoperative computer tomography, the diameter of the pars interarticularis at the thinnest location ranges from 3.5 mm to 5 mm. We therefore decided to modify the Buck’s method in order to cause minimal tissue damage and to enable the insertion of a 3-mm screw which, while allowing for a safe fixation of the defect, leaves a margin of bone. The main problem encountered in the use of a 1.1-mm guiding wire is its flexibility, which makes it impossible to move the wire seamlessly in one direction while running in bone tissue. The entry point in the bone is located far from the skin incision so that it is difficult to adjust the wire direction once it is in the soft tissues, which is why it is so important to be properly prepared for surgery by analysing CT to define the appropriate angle. During intraoperative fluoroscopy, we can choose the same bone landmarks as in CT and can accurately determine both the skin incision site, to allow a correct start, and the trajectory of the guide wire and drill. Preoperative planning also allows the surgeon to observe the possible obstacles (spinous processes, sacrum), he may encounter when inserting directional wire and screws. In the original Buck’s method, the point of entry of the screw is located on the lower edge of the lamina [4]. Anatomically this place, where yellow ligament adheres, is very narrow. In the open type of surgery, location of this point poses no difficulties, but in the closed method there is a substantial risk of violating the spinal canal. We therefore propose modification of the entry point of the screw, placing it on the lower end of the lower facet. An important aspect of our technique is that the use of fluoroscopy constitutes an improvement over the starting point proposed by Buck. Our results, both radiological and clinical, support the efficacy of the Buck’s method, but our proposed modification reduces the amount of soft tissue damage.

For patients who do not respond to conservative treatment, direct pars repair using Buck’s method with our modification, including adequate radiographic preparation, the use of a thin cannulated screw and changing the point of screw entry, allows precise and safe screw placement, regardless of the size of the bone at the defect site. Good functional results and a lack of complications support the clinical efficacy of our modifications.