Volumetric analysis of bilateral spinal canal decompression via hemilaminectomy versus laminoplasty in cervical spondylotic myelopathy

Investigation of the Efficacy of Bilateral Osteoligamentous Decompression via Hemilaminectomy in Cervical Spondylotic Myelopathy: A Clinical Study

OBJECTIVE

Cervical stability may deteriorate and kyphotic spinal deformities may develop in cervical spondylotic myelopathy (CSM) after laminectomy or laminoplasty. This study aimed to investigate the therapeutic efficacy of the "bilateral osteoligamentous decompression via unilateral hemilaminectomy approach (UHBOLD)" technique in CSM patients.

METHODS

The study included 34 adult patients who underwent UHBOLD surgery for CSM between 2016 and 2022. A record was made for all patients of age, gender, number of operated levels, preoperative and postoperative long-term follow-up VAS scores, Nurick grade values and mJOA scores, kyphosis angles measured on X-ray, and spinal canal areas measured on T2-weighted MR axial images.

RESULTS

Preoperative VAS scores of the patients were 6 (4-9), Nurick grade values were 3 (2-5), mJOA scores were 10.50 ± 3.42, kyphosis angles were -13.34 ± 13.69° and spinal canal areas were 87.11 ± 28.30 mm2. In postoperative long-term follow-up of these patients, VAS scores were 2 (1-5), Nurick grade values were 1 (0-5), mJOA scores were 13.94 ± 3.09, kyphosis angles were -15.07 ± 12.78° and spinal canal areas were 149.65 ± 42.57 mm2. A statistically significant difference was determined between the preoperative and the postoperative long-term follow-up VAS scores, Nurick grade values, mJOA scores, and spinal canal areas (P < 0.001). Kyphosis angles were not different (P = 0.198), and no instability was observed in any patient in long-term follow-up.

CONCLUSIONS

The UHBOLD technique performed in multilevel CSM patients did not cause any change in cervical lordosis angle in long-term follow-up, did not cause cervical kyphotic deformity or cervical instability, and significantly improved Nurick grade values, and VAS and mJOA scores.

Computerized Three-Dimensional Analysis: A Novel Method to Assess the Effect of Open-Door Laminoplasty

INTRODUCTION

The three-dimensional elaboration of morphological data derived from computed tomography (CT) and magnetic resonance imaging (MRI) scans generates virtual anatomical reconstructions. Here, we propose a novel protocol to analyze the postoperative results of open-door laminoplasty to evaluate differences in the volume of the spinal canal. The protocol uses geometric models in patients with cervical degenerative myelopathy before versus after cervical laminoplasty.

MATERIALS AND METHODS

Mimics and 3-Matic software (Materialise, Leuven, BE) programs were used to segment anatomical structures and create polygon meshes of spines. Patients with cervical spondylotic myelopathy were enrolled. The models obtained before and after laminoplasty were superimposed by using a global registration function. The magnitude of divergence was quantified by using the root-mean-square error (RMSE).

RESULTS

Using this novel protocol, we were able to map the differences in the volume of the spinal canal before laminoplasty and after laminoplasty and to quantify its magnitude and calculate the volumes.

DISCUSSION AND CONCLUSIONS

The development of a procedure to measure the space within the cervical bone walls using geometric parameters represents a new, powerful method to verify the results obtained by cervical laminoplasty. Further research horizons may include the routine use of virtual models in surgical planning for this procedure.

Cervical Oblique Corpectomy: Revitalizing the Underused Surgical Approach With Step-By-Step Simulation in Cadavers

ABSTRACT

Recently, the World Federation of Neurosurgical Societies Spine committee recommended that additional research on cost-benefit analysis of various surgical approaches for cervical spondylotic myelopathy be carried out and their efficacy with long-term outcomes be compared. Unfortunately, it is highly probable that the oblique corpectomy (OC) will not be included in cost-benefit investigations due to its infrequent application by neurosurgeons dealing with the spine. In this cadaveric study, head and necks of 5 adult human cadavers stained with colored latex and preserved in 70% alcohol solution were dissected under a table-mounted surgical microscope using 3× to 40× magnifications. The OC approach was performed to simulate real surgery, and the neurovascular structures encountered during the procedure and their relations with each other were examined. Oblique corpectomy was performed unilaterally, although neck dissections were performed bilaterally on 10 sides in all 5 cadavers. At each stage of the dissection, multiple three-dimensional photographs were obtained from different angles and distances. For an optimal OC, both the anterior spinal cord must be sufficiently decompressed and sufficient bone must be left in place to prevent instability in the cervical spine. Oblique corpectomy is a valid and potentially low cost alternative to other anterior and posterior approaches in the surgical treatment of cervical spondylotic myelopathy. However, meticulous cadaver studies are essential before starting real surgical practice on patients in order to perform it effectively and to avoid the risks of the technique.