Abstract
BackgroundThe area which located at the medial pedicle, posterior vertebral body and ventral hemilamina is defined as the hidden zone. Surgical management of hidden zone lumbar disc herniation (HZLDH) is technically challenging due to its difficult surgical exposure. The conventional interlaminar approach harbors the potential risk of post-surgical instability, while other approaches consist of complicated procedures with a steep learning curve and prolonged operation time.ObjectiveTo introduce microscopic extra-laminar sequestrectomy (MELS) technique for treatment of hidden zone lumbar disc herniation and present clinical outcomes.MethodsBetween Jan 2016 to Jan 2018, twenty one patients (13 males) with HZLDH were enrolled in this study. All patients underwent MELS (19 patients underwent sequestrectomy only, 2 patients underwent an additional inferior discectomy). The nerve root and fragment were visually exposed using MELS. The operation duration, blood loss, intra- and postoperative complications, and recurrences were recorded. The Visual Analog Scale (VAS), Oswestry Disability Index (ODI), and the modified MacNab criteria were used to evaluate clinical outcomes. Postoperative stability was evaluated both radiologically and clinically.ResultsThe mean follow-up period was 20.95 ± 2.09 (18–24) months. The mean operation time was 32.43 ± 7.19 min and the mean blood loss was 25.52 ± 5.37 ml. All patients showed complete neurological symptom relief after surgery. The VAS and ODI score were significantly improved at the final follow-up compared to those before operation (7.88 ± 0.70 vs 0.10 ± 0.30, 59.24 ± 10.83 vs 11.29 ± 3.59, respectively, p < 0.05). Seventeen patients (81%) obtained an “excellent” outcome and the remaining four (19%) patients obtained a “good” outcome based the MacNab criteria. One patient suffered reherniation at the same level one year after the initial surgery and underwent a transforaminal endoscopic discectomy. No major complications and postoperative instability were observed.ConclusionsOur observation suggest that MELS is safe and effective in the management of HZLDH. Due to its relative simplicity, it comprises a flat surgical learning curve and shorter operation duration, and overall results in reduced disturbance to lumbar stability.
Highlights
The area which located at the medial pedicle, posterior vertebral body and ventral hemilamina is defined as the hidden zone
The Visual Analog Scale (VAS) and Oswestry Disability Index (ODI) score were significantly improved at the final follow-up compared to those before operation (7.88 ± 0.70 vs 0.10 ± 0.30, 59.24 ± 10.83 vs 11.29 ± 3.59, respectively, p < 0.05)
Our observation suggest that microscopic extralaminar sequestrectomy (MELS) is safe and effective in the management of hidden zone lumbar disc herniation (HZLDH)
Summary
Patient recruitment We undertook a non-randomized prospective study, which was approved by the ethics committee of our institution (Spine surgery department, Yantai Affiliated Hospital of Binzhou Medical University). The inclusion criteria were as follows: (1) age > 18 years; (2) no previous history of spinal surgery; (3) MRI and CT identified the fragment was located in the hidden zone; (4) good general condition, no severe cardiopulmonary or hepatorenal dysfunction.Exclusion criteria were: (1) central stenosis (less than 10 mm) or lateral recess stenosis (less than 3 mm) confirmed by MR imaging and CT scans; (2) concomitant diseases involving systematic infection or malignant tumor; (3) segmental instability confirmed by dynamic radiographs. A 2–3 mm crescent-shaped lateral lamina was excised and ligamentum flavum was removed to expose the exiting nerve root and the ganglion, around which hemostasis with a bipolar was potentially needed. This exploration was performed in a caudal to cranial direction along the nerve root with a hook probe. All analyses were conducted using SPSS 19.0 software (SPSS, Inc., Chicago, IL, USA)
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
