Epidermal growth factor receptor-tyrosine kinase inhibitors (EGFR-TKIs) block downstream signaling pathways by inhibiting receptor tyrosine kinase activity, consequently suppressing proliferation, invasion and metastasis of tumor cells. EGFR-TKIs have been proven to be highly effective in patients with late non-small cell lung cancer (NSCLC) harboring EGFR sensitive mutations, significantly better than chemotherapy. Third-generation EGFR-TKIs, such as osimertinib, have emerged as the first-line treatment for advanced NSCLC patients with sensitive EGFR mutations. However, there are still some patients who exhibit primary resistance upon initial treatment with EGFR-TKIs. The exact mechanism of primary resistance remains unknown, and may be related to factors such as the structure of EGFR mutation subtypes, concurrent mutations, BIM deletion polymorphism, and high expression of programmed cell death-ligand 1. This review summarizes the molecular mechanisms of primary resistance to EGFR-TKIs and discusses potential therapeutic strategies, with the goal of optimizing precision targeted therapy for NSCLC patients.

BACKGROUND:Upper lumbar spinal stenosis is a multifactorial degenerative disorder of the spine.For narrowing of the spinal canal in the upper lumbar region(L1-L4),surgical decision-making is particularly complex.Existing minimally invasive surgeries each have their own advantages and limitations.Currently,there are few reports on biomechanical comparison and finite element analysis of different surgical methods for the treatment of high lumbar spinal stenosis.OBJECTIVE:To analyze the biomechanical impact of endoscopic unilateral laminotomy for bilateral decompression,transforaminal endoscopic lumbar decompression,and cross-overtop decompression in the treatment of upper lumbar spinal stenosis using endoscopy,and to verify the reliability and effectiveness of these three surgical techniques in treating upper lumbar spinal stenosis,providing a biomechanical basis for clinical decision-making.METHODS:The CT images of the lumbar spine of a healthy volunteer were selected,and the finite element model M0 of the normal lumbar L1-L5 segments was established using Mimics,Geomagic,Solid works,and Ansys software.The L2-L3 segment,representing upper lumbar characteristics,was chosen.Based on this model,the surgical models for endoscopic unilateral laminotomy for bilateral decompression(M1),transforaminal endoscopic lumbar decompression(M2),and cross-overtop decompression(M3)were established.Using software,the changes in the range of motion of the entire lumbar segment and the maximum Von Mises stress of the intervertebral discs were simulated and evaluated for each group of models under six loading conditions:flexion,extension,left lateral bending,right lateral bending,left rotation,and right rotation.RESULTS AND CONCLUSION:(1)Compared with model MO,the range of motion in M1,M2,and M3 increased under all six conditions,with M1 showing a greater increase.(2)M1 and M2 demonstrated significant increases in range of motion under forward bending,extension,and right rotation,while the increase under other conditions remained below 7％.(3)Compared with model M3,model M1 exhibited slightly increased overall joint range of motion during extension and left bending,while no significant changes were observed in other aspects,and the L1-L5 lumbar segments did not reach an unstable state.(4)In model M1,the maximum Von Mises stress of the intervertebral discs increased most significantly under flexion and extension loading conditions.However,under left lateral bending,right lateral bending,left rotation,and right rotation loading conditions,the increase did not exceed 5％.(5)These findings suggest that due to the sagittal anatomical characteristics of the facet joints,the unilateral laminotomy for bilateral decompression technique,while decompressing,involves resection of more facet joints,which impacts overall segmental stability.The transforaminal endoscopic lumbar decompression technique is suitable for patients with foraminal stenosis but cannot achieve complete decompression for those with severe ventral central stenosis.The Cross-Overtop technique effectively enlarges the volume of the central canal and lateral recess,optimizing decompression,and shows unique advantages in treating upper lumbar spinal stenosis.

BACKGROUND:Upper lumbar spinal stenosis is a multifactorial degenerative disorder of the spine.For narrowing of the spinal canal in the upper lumbar region(L1-L4),surgical decision-making is particularly complex.Existing minimally invasive surgeries each have their own advantages and limitations.Currently,there are few reports on biomechanical comparison and finite element analysis of different surgical methods for the treatment of high lumbar spinal stenosis.OBJECTIVE:To analyze the biomechanical impact of endoscopic unilateral laminotomy for bilateral decompression,transforaminal endoscopic lumbar decompression,and cross-overtop decompression in the treatment of upper lumbar spinal stenosis using endoscopy,and to verify the reliability and effectiveness of these three surgical techniques in treating upper lumbar spinal stenosis,providing a biomechanical basis for clinical decision-making.METHODS:The CT images of the lumbar spine of a healthy volunteer were selected,and the finite element model M0 of the normal lumbar L1-L5 segments was established using Mimics,Geomagic,Solid works,and Ansys software.The L2-L3 segment,representing upper lumbar characteristics,was chosen.Based on this model,the surgical models for endoscopic unilateral laminotomy for bilateral decompression(M1),transforaminal endoscopic lumbar decompression(M2),and cross-overtop decompression(M3)were established.Using software,the changes in the range of motion of the entire lumbar segment and the maximum Von Mises stress of the intervertebral discs were simulated and evaluated for each group of models under six loading conditions:flexion,extension,left lateral bending,right lateral bending,left rotation,and right rotation.RESULTS AND CONCLUSION:(1)Compared with model MO,the range of motion in M1,M2,and M3 increased under all six conditions,with M1 showing a greater increase.(2)M1 and M2 demonstrated significant increases in range of motion under forward bending,extension,and right rotation,while the increase under other conditions remained below 7％.(3)Compared with model M3,model M1 exhibited slightly increased overall joint range of motion during extension and left bending,while no significant changes were observed in other aspects,and the L1-L5 lumbar segments did not reach an unstable state.(4)In model M1,the maximum Von Mises stress of the intervertebral discs increased most significantly under flexion and extension loading conditions.However,under left lateral bending,right lateral bending,left rotation,and right rotation loading conditions,the increase did not exceed 5％.(5)These findings suggest that due to the sagittal anatomical characteristics of the facet joints,the unilateral laminotomy for bilateral decompression technique,while decompressing,involves resection of more facet joints,which impacts overall segmental stability.The transforaminal endoscopic lumbar decompression technique is suitable for patients with foraminal stenosis but cannot achieve complete decompression for those with severe ventral central stenosis.The Cross-Overtop technique effectively enlarges the volume of the central canal and lateral recess,optimizing decompression,and shows unique advantages in treating upper lumbar spinal stenosis.

Objective To explore the clinical effectiveness of full endoscopic lamina fenestration discec-tomy(Endo-LOVE)in combination with nerve root pulsed radiofrequency(NR-PRF)in the treatment of lumbar degenerative disease(LDD),along with the amelioration of postoperative residual symptoms.Methods A retro-spective analysis was performed on 102 patients with LDD who were treated in our hospital between January 2022 and June 2023.Among them,53 cases were assigned to the observation group(receiving Endo-LOVE combined with NR-PRF),and 49 cases were included in the control group(undergoing Endo-LOVE alone).The mean follow-up period was 15.05±1.15 months.The general data of the two groups were compared.Observations were carried out at preoperative,1-day,7-day,1-month,3-month,6-month,and final follow-up time points postopera-tively.The perioperative data and follow-up outcomes of the two groups were compared.Results Prior to surgery,no significant disparities were detected in the general conditions and clinical observation indicators(VAS,M-JOA,and ODI scores)between the two groups.Postoperatively,both groups exhibited a notable improvement in clinical indicators when compared to the preoperative levels(P<0.05).Within three months after surgery,the observation group showed significantly more pronounced improvement in all clinical indicators than the control group(P<0.05).At six months postoperatively and during the final follow-up,no statistically significant differences in clinical indi-cators were found between the two groups.Moreover,at the final follow-up,there was no statistically significant difference in the Macnab scores between the two groups(P>0.05).Conclusion Endoscopic decompression for the treatment of LDD exhibits high safety and reliability.When combined with endoscopic NR-PRF,it enhances the clinical efficacy,reduces the incidence of postoperative residual symptoms,and facilitates rapid postoperative recovery.This complementary combination presents a novel therapeutic strategy for LDD.

Objectives:To investigate the clinical efficacies of endoscopic cross-overtop decompression(Cross-overtop)and endoscopic unilateral laminotomy bilateral decompression(Endo-ULBD)in the treatment of severe lumbar spinal stenosis.Methods:A retrospective study was conducted on the patients with single-level severe lumbar spinal stenosis admitted and treated with Cross-overtop decompression(30 cases)and En-do-ULBD(30 cases)in our hospital between July 2021 and December 2022.There were 37 male cases and 23 female cases.The average age of the Cross-overtop group was 66.2±8.8 years,and the average age of the Endo-ULBD group was 71.4±8.7 years.The patients were followed up at 1 week,3 months,6 months,and≥ 12 months(final)after operation.Clinical outcomes were assessed using the visual analog scale(VAS)score,Oswestry disability index(ODI),and Japanese Orthopaedic Association(JOA)scores.The sagittal diameter of the affected spinal canal was measured to evaluate central canal expansion.Postoperative excellent and good rate of efficacy were determined using the MacNab criteria at 12 months'or the final follow-up.Results:All 60 patients completed follow-up with a duration ranging from 12 to 25 months.Both groups showed significant improvements in VAS scores for low back and leg pain and ODI at each follow-up interval compared to the previous assessment.The Cross-overtop group demonstrated a greater expansion rate(5.08％)of the sagittal di-ameter of the central canal at the affected level compared to the Endo-ULBD group(1.59％),with statistically significant differences(P＜0.05).At postoperative 12-month or final follow-up,MacNab evaluation revealed an excellent and good rate of 90.0％in the Cross-overtop group and 83％in the Endo-ULBD group.Conclusions:Cross-overtop decompression is one of the minimally invasive endoscopic surgical techniques for treating severe lumbar spinal stenosis,which is safe and effective with distinct advantages.

Objective To explore the clinical effectiveness of full endoscopic lamina fenestration discec-tomy(Endo-LOVE)in combination with nerve root pulsed radiofrequency(NR-PRF)in the treatment of lumbar degenerative disease(LDD),along with the amelioration of postoperative residual symptoms.Methods A retro-spective analysis was performed on 102 patients with LDD who were treated in our hospital between January 2022 and June 2023.Among them,53 cases were assigned to the observation group(receiving Endo-LOVE combined with NR-PRF),and 49 cases were included in the control group(undergoing Endo-LOVE alone).The mean follow-up period was 15.05±1.15 months.The general data of the two groups were compared.Observations were carried out at preoperative,1-day,7-day,1-month,3-month,6-month,and final follow-up time points postopera-tively.The perioperative data and follow-up outcomes of the two groups were compared.Results Prior to surgery,no significant disparities were detected in the general conditions and clinical observation indicators(VAS,M-JOA,and ODI scores)between the two groups.Postoperatively,both groups exhibited a notable improvement in clinical indicators when compared to the preoperative levels(P<0.05).Within three months after surgery,the observation group showed significantly more pronounced improvement in all clinical indicators than the control group(P<0.05).At six months postoperatively and during the final follow-up,no statistically significant differences in clinical indi-cators were found between the two groups.Moreover,at the final follow-up,there was no statistically significant difference in the Macnab scores between the two groups(P>0.05).Conclusion Endoscopic decompression for the treatment of LDD exhibits high safety and reliability.When combined with endoscopic NR-PRF,it enhances the clinical efficacy,reduces the incidence of postoperative residual symptoms,and facilitates rapid postoperative recovery.This complementary combination presents a novel therapeutic strategy for LDD.

Objectives:To investigate the clinical efficacies of endoscopic cross-overtop decompression(Cross-overtop)and endoscopic unilateral laminotomy bilateral decompression(Endo-ULBD)in the treatment of severe lumbar spinal stenosis.Methods:A retrospective study was conducted on the patients with single-level severe lumbar spinal stenosis admitted and treated with Cross-overtop decompression(30 cases)and En-do-ULBD(30 cases)in our hospital between July 2021 and December 2022.There were 37 male cases and 23 female cases.The average age of the Cross-overtop group was 66.2±8.8 years,and the average age of the Endo-ULBD group was 71.4±8.7 years.The patients were followed up at 1 week,3 months,6 months,and≥ 12 months(final)after operation.Clinical outcomes were assessed using the visual analog scale(VAS)score,Oswestry disability index(ODI),and Japanese Orthopaedic Association(JOA)scores.The sagittal diameter of the affected spinal canal was measured to evaluate central canal expansion.Postoperative excellent and good rate of efficacy were determined using the MacNab criteria at 12 months'or the final follow-up.Results:All 60 patients completed follow-up with a duration ranging from 12 to 25 months.Both groups showed significant improvements in VAS scores for low back and leg pain and ODI at each follow-up interval compared to the previous assessment.The Cross-overtop group demonstrated a greater expansion rate(5.08％)of the sagittal di-ameter of the central canal at the affected level compared to the Endo-ULBD group(1.59％),with statistically significant differences(P＜0.05).At postoperative 12-month or final follow-up,MacNab evaluation revealed an excellent and good rate of 90.0％in the Cross-overtop group and 83％in the Endo-ULBD group.Conclusions:Cross-overtop decompression is one of the minimally invasive endoscopic surgical techniques for treating severe lumbar spinal stenosis,which is safe and effective with distinct advantages.

Objective To investigate the effect of facet joint resection at different ranges under endoscopy on the stability of the cervical spine and provide a biomechanical theoretical basis for clinical surgery.Methods A normal finite element model of the cervical spine C5-6 was established based on CT data,and unilateral facetectomy models with different ranges(0,25％,50％,75％,and 100％)of laminectomy were obtained(Models 1-5)by simulating cervical endoscopic surgery.The ranges of motion(ROMs)of C5-6 and the von Mises stresses of the discs for the models in each group were compared and analyzed.Results Except for flexion,Models 1 and 2 showed insignificant changes in ROMs and disc von Mises stresses in each direction compared with those of the normal model.Model 3 showed a noticeable increase in ROMs and disc von Mises stresses in each direction compared with those of the normal model:ROMs under flexion,extension,left lateral bending,right lateral bending,left rotation,and right rotation increased by 27％,4％,3％,13％,5％,and 16％,respectively,and von Mises stresses increased by 32％,4％,2％,5％,9％,and 5％,respectively.Models 4 and 5 exhibited a significant increase in the ROMs and disc von Mises stresses in each direction compared to the normal model.For Model 4,ROMs were increased by 27％,14％,6％,24％,7％,167％,and von Mises stresses were increased by 33％,13％,3％,32％,10％,130％.For Model 5,ROMs were increased by 27％,17％,6％,25％,7％,167％,and von Mises stresses were increased by 33％,29％,8％,33％,12％,138％.Conclusions As the range of unilateral facetectomy increased,cervical ROM and disc von Mises stress extremum gradually increased.The cervical spine shows a significant ROM increase and stress changes when facet joint resection on one side exceeds 1/2.More than 1/2 of the facet joint should be preserved during surgery to avoid medical instability.

BACKGROUND:Platelet-rich plasma can promote the repair and regeneration of intervertebral disc tissue.Percutaneous transforaminal endoscopic discectomy is widely used in the treatment of lumbar disc herniation.In recent years,more and more scholars have focused on the combined treatment of lumbar disc herniation with the two techniques in order to achieve a better patient prognosis. OBJECTIVE:To investigate the clinical safety and effectiveness of percutaneous transforaminal endoscopic discectomy combined with platelet-rich plasma in the treatment of lumbar disc herniation. METHODS:The clinical data of 58 patients with lumbar disc herniation who met the inclusion and exclusion criteria at Sixth Medical Center of PLA General Hospital from June 2017 to May 2018 were retrospectively analyzed.Among them,29 patients underwent percutaneous transforaminal endoscopic discectomy combined with platelet-rich plasma(observation group),and the remaining 29 patients underwent percutaneous transforaminal endoscopic discectomy only(control group).Visual Analogue Scale score for back and leg pain,lumbar JOA score,and Oswestry Disability Index were evaluated preoperatively,at 3,6,and 12 months postoperatively,and at the last follow-up.Intervertebral space height,nucleus pulposus to cerebrospinal fluid signal strength ratio,and intervertebral disc Pfirrmann grading were measured preoperatively,at 6 and 12 months postoperatively,and at the last follow-up.The modified MacNab criteria were used to assess excellent and good rate of curative effect at the last follow-up. RESULTS AND CONCLUSION:(1)The Visual Analogue Scale score for back and leg pain,JOA score,and Oswestry Disability Index of the two groups postoperatively were significantly improved compared with those preoperatively(P<0.05).Visual Analogue Scale score and Oswestry Disability Index were lower in the observation group than those in the control group at 3 and 6 months postoperatively(P<0.05).The JOA score was higher in the observation group than that in the control group at 3 and 6 months postoperatively(P<0.05).(2)The nucleus pulposus to cerebrospinal fluid signal strength ratio was higher in the observation group than that in the control group at the last follow-up(P<0.05).Pfirrmann grading of the intervertebral discs was better in the observation group than that in the control group(P<0.05).The excellent and good rate was 93%in the observation group and 83%in the control group,and the difference was not statistically significant(P>0.05).(3)These findings indicate that percutaneous transforaminal endoscopic discectomy combined with platelet-rich plasma in the treatment of lumbar disc herniation has satisfactory clinical efficacy and can delay the degeneration of the intervertebral disc to a certain extent.

BACKGROUND:In clinical application,simple interspinous fixation without additional interbody fusion has similar fixation effects to pedicle screw and rod fusion internal fixation,and can effectively reduce the range of motion of the responsible segment and the stress of the articular process.However,after simple placement of the new interspinous fusion fixation device BacFuse,the stress at the root of the spinous process is relatively concentrated,and the spinous fracture is prone to occur.If an intervertebral fusion cage is inserted in conjunction with interspinous fixation,Von Mises stress can theoretically be dispersed to reduce the risk of spinous fracture.However,there are few studies on biomechanics and finite element analysis. OBJECTIVE:To observe the biomechanical stability of interspinous fixation-assisted endoscopic interbody fusion in the treatment of severe lumbar spinal stenosis. METHODS:The normal finite element model M0 of the L4-L5 segment of the lumbar spine was established by Mimics,Geomagic,Solidworks,and ANSYS software based on the lumbar CT images of a 26-year-old adult male volunteer excluding spinal diseases.On the basis of M0,the immediate model M1 after endoscopic decompression combined with interbody fusion,the interspinous fixation device(BacFuse)model M2 after endoscopic decompression,and the interspinous fixation(BacFuse)model M3 after endoscopic-assisted interbody fusion were established.The same stress was applied to the upper surface of the L4 vertebral body in the four groups,and the lower surface of the L5 vertebral body was fixed and supported.The range of motion and the extreme Von Mises stress of the endplate bone and the posterior ligament complex of the vertebral body were analyzed under six working conditions of flexion,extension,left/right bending,and left/right rotation. RESULTS AND CONCLUSION:(1)Compared with model M0,the range of motion value of model M1 increased significantly under six working conditions.Model M2 and model M3 had a significant reduction in range of motion.(2)Compared with model M0,the maximum stress of the vertebral body in model M1 did not change significantly under the six working conditions.The maximum stress at the rear of the M2 vertebral body increased significantly.(3)Compared with model M1,the maximum stress of model M3 did not change significantly under the six working conditions.Compared with model M2,the maximum stress of model M3 decreased significantly.(4)Compared with the model M0,the extreme Von Mises stress of the L4 and L5 endplates of the model M1 was significantly increased.The extreme Von Mises stress in L4 and L5 endplates of models M2 and M3 decreased slightly.Compared with model M1,the Von Mises stress of the bone under the L4 and L5 endplate of models M2 and M3 was significantly reduced.(5)It is concluded that the implantation of BacFuse can effectively reduce the bone stress under the endplate during simple interbody fusion,decrease the risk of cage subsidence,diminish the risk of facet joint fracture on the decompression side,and provide a good stable environment for interbody fusion.The placement of an intervertebral fusion cage can reduce the stress of the root of the spinous process,which is beneficial to decrease the risk of fracture of the root of the spinous process.