Lower motor neuron lesion caused by single level lower thoracic disc protrusion / 中华骨科杂志

ABSTRACT

Objective To investigate clinical features of lower motor neuron lesion (LMNL) caused by the single level lower thoracic disc protrusion (LTDP),and to observe clinical outcomes of surgical treatment.Methods Between January 1997 and December 2009,17 patients with LMNL caused by single level LTDP underwent en bloc resection of the superior articular process,Cave-in 360° circumferential decompression and internal fixation in our hospital.MRI and CT scans were taken to confirm lesion levelsT10-11 in 4 patients of whom 3 had patellar clonus and ankle clonus,T11-12 in 5 patients of whom 4 had ankle clonus,and T12L1 in 8 patients who only had positive Babinski sign.The neurologic status was assessed using the Japanese Orthopaedic Association (JOA) scoring system.The muscle strength of the tibialis anterior was assessed using the Manual Muscle Test (MMT).Sagittal Cobb angle and cross-sectional area of the dural sac at the level of maximal compression in MRI were also observed.Results All patients were followed up for 22 to 76 months (average,48.6 months).The mean JOA score increased from preoperative 5.88±1.11 to 9.53±0.94 at final follow-up (t=16.143,P＜0.05).The muscle strength of the tibialis anterior recovered to more than grade 4 in all patients.Postoperative Cobb angle was unchanged compared with that before operation.MRI indicated that the cross-sectional area of the dural sac at the level of maximum compression increased from preoperative 35.8±7.3 mm2 to postoperative 132.9±6.5 mm2 (t=70.78,P＜0.05).Conclusion LMNL can be caused by LTDP.The eu bloc resection of the superior articular process,Cave-in 360° circumferential decompression and internal fixation can provide a satisfactory decompression effect and marked recovery of neurological function.