Novel Approach Posterior Percutaneous Endoscopic Cervical Discectomy:Surgical Approach Design,Biomechanical Study And Clinical Application

Part I The Surgical Approach Design and Biomechanical Research of Lamina-hole PECDObjectiveTo evaluate the changes in strength and resistance to violence of the pedicle after Lamina-hole PECD,to evaluate its safety and feasibility.Methods1.9 freshly frozen cervical cadaver specimens were selected.The muscles,fascia and other soft tissues were removed.C4-C6 vertebrae are separated from the cervical spine,a total of 27 cervical vertebrae specimens were selected.2.27 vertebrae were randomly divided into three groups.Blank control group:no operation was performed,the anatomical structure was intact;Lamina-hole surgery group:lamina-hole approach was performed.Pedicle fracture group:the pedicle of one side was cut to fracture.3.Cervical vertebral specimens were clamped with a special mold,and the pedicle strength of the three groups was tested with a biomechanical material experiment machine.ResultsIn the blank control group,the compressive force at break of the pedicle was 468.9±82.2N,it was 400.8±70.2N in the Lamina-hole group,and 179.7±52.7N in the pedicle fracture group.There was no significant difference between the compressive force at break of the pedicle of the Lamina-hole group and the blank control group(P>0.05).On the other hand,the compressive force at the break of the pedicle of the pedicle fracture group was significantly decreased compared with the blank control group(P<0.05).ConclusionsIn a Lamina-hole PECD surgery,the strength of the pedicle was not significantly reduced when the lateral cortex of the pedicle was preserved.However,when the pedicle was broken,the pedicle’s overall resistance to violence was significantly reduced.Part Ⅱ The clinical research of Lamina-hole PECDObjectiveThe optimal PECD surgical approach for CIVDH remains controversial.The conventional posterior K-hole approach for PECD leads to damage of facet joint.This paper is to first describe a novel posterior lamina-hole approach of percutaneous endoscopic cervical discectomy for cervical intervertebral disc herniation(CIVDH).To evaluate the feasibility and short-term clinical effect of this approach.MethodsSingle-center retrospective observational study of all patients managed with PPECD using the lamina-hole approach for symptomatic single-level CIVDH between January 2015 and January 2016.The clinical outcomes were evaluated with the visual analog scale,modified MacNab criteria,and radiographical results.A total of 12 consecutive patients(7 women,5 men)with symptomatic CIVDH were treated.All PECD procedures were performed by the same surgeon.Technical success was defined as the ability to access the lesion and removal of the herniated fragment using the approach.In addition to the those previously reported preoperative preparations,discography was performed for all the enrolled patients.A cervical computed tomographic scan and sagittal reconstruction were obtained less than 2 hours after the injection of discography.After general anesthesia,continuous intraoperative electromyogram,somatosensory-evoked potentials,and intermittent transcranial motor-evoked potentials were monitored.The entire surgical process was controlled with C-arm fluoroscopy.Follow-up examinations were conducted at day 1 and months 3,6 after surgery.The patients came personally to the clinic for follow-up examinations.The visual analog scale(VAS)for neck and arm pain and the modified MacNab criteria were used to evaluate the postoperative effects.During follow-up at 1 and 6 months postoperatively,neutral and dynamic cervical radiographs of each patient were obtained.After operations,all of the patients received MRM examination in 24 hours to confirm complete decompression of pinched nerve root and dural sac.Also,all patients underwent MRI and CT after the end of the follow-up period.Wilcoxon matched-pairs signed rank test was applied for analysis.Results12 patients were included in the follow-up and completed all follow-up visits.Positive clinical response for pain relief was achieved in these patients in whom posterior percutaneous endoscopic cervical discectomy through lamina-hole approach had been performed.The mean VAS score at baseline was 87.91 ± 7.88,16.58 ± 1,78 at 1 day,9.83± 4.11 at 1 week,7.00 ± 6.62 at 1 month,5.00±4.81 at 3 months and 4.67±4.10 at 6 months(Figure 5).VAS improved statistically significantly 1 day after surgery(P<0.001),improvement of VAS at the interval between 1day and 1 week was statistically significant(P<0.05).ConclusionsAs an alternative surgical approach of PPECD,PPECD through lamina-hole approach is a novel access for CIVDH and may be considered a valid and safe therapeutic option for cervical intervertebral disc herniation.The advantages of this approach are not only providing a valid and secure access to herniated cervical intervertebral fragment but also avoiding the iatrogenic damage to the facet joint and relevant functional spinal unit(FSU).Theoretically,the potential of secondary degeneration of FSU is low.