Die mikrochirurgische Dekompression ist eine etablierte Operation für die Behandlung von Patienten mit einer lumbalen Spinalkanalstenose. Das klinische Resultat der Operation ist gut. Jedoch erfahren 30-40% der Patienten keine signifikante Besserung der Beschwerden postoperativ. Die Gründe hierfür sind unklar. Angenommen wird ein Zusammenhang mit den individuellen anatomischen Gegebenheiten der Patienten. Die unterschiedlichen Typen des Sagittalen Profils wurden von Roussouly definiert (Typ 1-4) und spielen bei unterschiedlichen Krankheitsbildern eine wichtige Rolle. Der Einfluss des Sagittalen Profils auf Patienten, die eine mikrochirurgische Dekompression der lumbalen Spinalkanalstenose erhalten haben, wurde bisher nicht erforscht und sollte in dieser Studie als Einflussfaktor auf das klinische Resultat untersucht werden.
OBJETICVE The microsurgical decompression for patients with symptomatic lumbar spinal stenosis is a well-established surgery. In general, the operation shows a good clinical outcome. However, 30-40% of patients do not benefit after surgical decompression. This could be related to different anatomical preconditions of the patients. Well-known anatomical parameters are the sagittal profile types defined by Roussouly. There are four sagittal profile types (SPT 1-4), which are defined due to their spinopelvic parameters. The sagittal profile types have already been shown to influence in the surgical results in degenerative disc disease. In our study we investigated the influence of the sagittal profile type in patients, who suffered from lumbar spinal stenosis and received a microsurgical decompression. METHODS One hundred patients were analyzed retrospectively. All of them suffered from symptomatic lumbar spinal stenosis and were treated via a microsurgical decompression. Preoperative lateral spinal radiographs were performed. Patients were assigned to one of four groups according to their sagittal profile type. Furthermore, pre- and postoperative outcome scales, including the walking distance, visual analog scale (VAS), Roland-Morris Disability Questionnaire, Oswestry Disability Index, Odom’s criteria and the 36-Item Short-Form Health Survey score (SF-36) were analyzed. RESULTS 70-80% of the patients with sagittal profile type 2-4 were satisfied with the surgical results after microsurgical decompression. However, only 43% of the patients with sagittal profile type 1 were satisfied. This is reflected in significant worse clinical outcome scores concerning their back-pain related disability and postoperative back pain (VASback-SPT 1 = 5.4 ± 2.8; VASback-SPT 2 = 2.6 ± 1.9; VASback-SPT 3 = 2.9 ± 2.6; VASback-SPT 4 = 1.5 ± 2.5). CONCLUSIONS Patients with sagittal profile type 1, a small pelvic incidence and reduced compensation mechanisms show a distinct lordosis in the lower lumbar spine and a long thoracolumbar kyphosis. This results in a high axial load and a high load on dorsal structures of the lower lumbar spine with a high load on dorsal structures. A dorsal surgical approach to the lumbar spine can increase low back pain. Patients with these anatomical preconditions, who received a microsurgical decompression present with a significantly worse clinical outcome. Therefore, the decision for microsurgical decompression should be evaluated carefully. Potentially a surgical fusion should be considered. Other possibilities for back pain should be taken into account as well and should be carefully evaluated and treated.
