Anterior percutaneous full-endoscopic transcorporeal decompression for cervical disc herniation: a finite element analysis and long-term follow-up study.

OBJECTIVE: The purpose of this study was to investigate the long-term consequences on the cervical spine after Anterior transcorporeal percutaneous endoscopy cervical discectomy (ATc-PECD) from the biomechanical standpoint. METHODS: A three-dimensional model of the normal cervical spine C2-T1 was established using finite element method. Subsequently, a disc degeneration model and degeneration with surgery model were constructed on the basis of the normal model. The same loading conditions were applied to simulate flexion, extension, lateral bending and axial rotation of the cervical spine. We calculated the cervical range of motion (ROM), intradiscal pressure, and intravertebral body pressure under different motions for observing changes in cervical spine biomechanics after surgery. At the same time, we combined the results of a long-term follow-up of the ATc-PECD, and used imaging methods to measure vertebral and disc height and cervical mobility, the Japanese Orthopaedic Association (JOA) score and visual analog scale (VAS) score were used to assess pain relief and neurological functional recovery. RESULTS: The long-term follow-up results revealed that preoperative JOA score, neck VAS score, hand VAS score, IDH, VBH, and ROM for patients were 9.49 ± 2.16, 6.34 ± 1.68, 5.14 ± 1.48, 5.95 ± 0.22 mm, 15.41 ± 1.68 mm, and 52.46 ± 9.36° respectively. It changed to 15.71 ± 1.13 (P < 0.05), 1.02 ± 0.82 (P < 0.05), 0.77 ± 0.76 (P < 0.05), 4.73 ± 0.26 mm (P < 0.05), 13.67 ± 1.48 mm (P < 0.05), and 59.26 ± 6.72° (P < 0.05), respectively, at 6 years postoperatively. Finite element analysis showed that after establishing the cervical spondylosis model, the overall motion range for flexion, extension, lateral bending, and rotation decreased by 3.298°, 0.753°, 3.852°, and 1.131° respectively. Conversely, after establishing the bone tunnel model, the motion range for these actions increased by 0.843°, 0.65°, 0.278°, and 0.488° respectively, consistent with the follow-up results. Moreover, analysis of segmental motion changes revealed that the increased cervical spine mobility was primarily contributed by the surgical model segments. Additionally, the finite element model demonstrated that bone tunneling could lead to increased stress within the vertebral bodies and intervertebral discs of the surgical segments. CONCLUSIONS: Long-term follow-up studies have shown that ATc-PECD has good clinical efficacy and that ATc-PECD can be used as a complementary method for CDH treatment. The FEM demonstrated that ATc-PECD can lead to increased internal stresses in the vertebral body and intervertebral discs of the operated segments, which is directly related to cervical spine degeneration after ATc-PECD.

Camelliazijinica (Theaceae), a new species endemic to Danxia landscape from Guangdong Province, China.

A new species of the genus Camellia (Theaceae), Camelliazijinica, discovered in the Danxia landscape from Guangdong Province, China, is characterized and illustrated. Phylogenetic analysis based on chloroplast genomes suggested its affinity with C.drupifera, C.oleifera and C.fluviatilis, however, it morphologically differs from all of the latter by leaf shape and size. Phonologically, it most closely resembles C.microphylla, but can be distinguished from the latter by its young branchlets glabrous (vs. densely pubescent), fewer bracteoles and sepals, diverse leaf shape, midvein raised slightly with sparsely pubescent or glabrous (vs. prominently with densely pubescent) and leaf adaxially matt (vs. vernicose) when dried. By morphological and molecular analyses, Camelliazijinica represented a distinct new species of C.sect.Paracamellia.

Lysimachiadanxiashanensis, a new species of Primulaceae from Guangdong, China.

Lysimachiadanxiashanensis, a new Primulaceae species, endemic to the Danxia landscape in Guangdong Province, China, is described and illustrated. This new species is morphologically similar to L.pseudohenryi, L.phyllocephala, L.congestiflora and L.kwangtungensis, but it differs from the similar species by its purplish-red plants, petiole without wings, calyx with orange glandular and the corolla margin serrated on upper half with orange-red glandular punctates. This new species belongs to Lysimachiasubgen.Lysimachiasect.Nummularia. Phylogenetic analysis confirmed that L.danxiashanensis is a distinct clade, based on the combined data of ITS and rbcL sequences. The conservation status of the new species was evaluated as Endangered (EN) according to IUCN Red List Categories and Criteria.

Aspleniumguodanum (Aspleniaceae), a distinct new fern species from northern Guangdong, China, based on morphological data and molecular phylogeny.

A new spleenwort species, Aspleniumguodanum, was found and described from Danxia landform region in Guangdong, China. The new species has close resemblance to A.subcrenatum Ching ex S.H.Wu in morphology, but can be distinguished by having plants small, stipes and rachises not covered with fibrous scales, relatively fewer pairs of pinnae, pinnae short, pinna margin weakly biserrate, pinna apex acute and lower pinnae obviously reduced. Phylogenetic analyses, based on six plastid markers (atpB, rbcL, rps4 & rps4-trnS and trnL & trnL-F) of the new species and its relatives, support a close relationship between A.guodanum and A.subcrenatum. Only one population with no more than 50 individuals were found and, therefore, it is recommended to be classified as Critically Endangered (CR) following IUCN Red List Criteria.

Surgical Essentials and 2-Year Follow-Up Results of Channel Repair in Endoscopic Transcorporeal Discectomy for Cervical Disc Herniation.

OBJECTIVE: To evaluate long-term outcomes and surgical essentials of channel repair in endoscopic transcorporeal discectomy for cervical disc herniation. METHODS: From October 2019 to March 2020, 24 patients with cervical disc herniation underwent channel repair after percutaneous full-endoscopic anterior transcorporeal cervical discectomy. Five interventions were performed at C3-C4, 11 were performed at C4-C5, and 8 were performed at C5-C6. Clinical outcomes were evaluated by Neck Disability Index, Japanese Orthopaedic Association, and visual analog scale scores. Radiologic changes were evaluated with intervertebral disc height and drilled vertebral height. RESULTS: All procedures were completed with a mean operating time of 86.40 ± 8.19 minutes. Swollen neck was observed in 5 patients, which resolved within 2 hours. At the final follow-up, Neck Disability Index, Japanese Orthopaedic Association, and visual analog scale scores were improved significantly compared with preoperative assessments (P < 0.05); intervertebral disc height was decreased significantly (P < 0.05); and loss of drilled vertebral height was not significant (P > 0.05). All 24 bony channels disappeared by 3 months postoperatively. No other complications were observed. CONCLUSIONS: Percutaneous full-endoscopic anterior transcorporeal cervical discectomy with channel repair offers a minimally invasive and effective treatment option for patients with cervical disc herniation. This technique demonstrates favorable clinical outcomes, including preservation of cervical spine mobility and minimal complications. Although there was a significant loss of intervertebral disc height, no vertebral collapse occurred. Strict adherence to surgical indications and precautions is crucial for successful outcomes. Further research and long-term studies are required to validate the efficacy and safety of this approach in a larger patient population.

Anterior Percutaneous Full-Endoscopic Transcorporeal with Single-Incision Treatment for Noncontiguous 2-Level Cervical Disc Herniation: Technical Report and Early Follow-Up.

BACKGROUND: Noncontiguous 2-level cervical disc herniation (NCT-CDH) is a common condition that often requires surgical intervention. In this study, we developed a surgical approach for the treatment of NCT-CDH using anterior percutaneous full-endoscopic single incision through the vertebral body. We provide a brief overview of its safety, efficacy, and feasibility, along with a description of our relevant surgical experience. METHODS: A retrospective study was conducted, involving 30 patients who were followed up for at least 12 months. Preoperative and postoperative visual analog scale, Japanese Orthopedic Association scores, Nurick scores, intervertebral disc height, and modified Macnab criteria were recorded. Patients underwent regular radiological evaluations throughout the follow-up period. RESULTS: Postoperative computed tomography, magnetic resonance imaging, and X-ray examinations revealed bone tunnel healing, intact drilled vertebral bodies without collapse, adequate decompression of the spinal canal, and normal cervical mobility. There was a significant improvement in postoperative visual analog scale, Japanese Orthopedic Association scores, Nurick scores, and modified Macnab criteria compared to the preoperative values (P < 0.05). CONCLUSIONS: Our study revealed that the anterior percutaneous full-endoscopic transcorporeal with single-incision treatment for NCT-CDH is a safe and feasible surgical method. Therefore, it can be considered as a viable treatment option for patients with NCT-CDH.

Anterior transcorporeal approach combined with posterior translaminar approach in percutaneous endoscopic cervical discectomy for two-segment cervical disc herniation treatment: a technical report and early follow-up.

OBJECTIVE: Full endoscopic techniques are being gradually introduced from single-segment cervical disc herniation surgery to two-segment cervical disc herniation surgery. However, there is no suitable full endoscopic treatment for mixed-type two-segment cervical disc herniation (MTCDH) in which one segment herniates in front of the spinal cord and the other segment herniates behind the spinal cord. Therefore, we introduce a new full endoscopic technique by combining an anterior transcorporeal approach and a posterior translaminar approach. In addition, we provide a brief description of its safety, efficacy, feasibility, and surgical points. METHODS: Thirty patients with MTCDH were given full endoscopic surgical treatment by a combined transcorporeal and transforaminal approach and were followed up for at least 12 months. RESULTS: Clinical assessment scales showed that the patient's symptoms and pain were significantly reduced postoperatively. Imaging results showed bony repair of the surgically induced bone defect and the cervical Cobb angle was increased. No serious complications occurred. CONCLUSION: This technique enables minimally invasive surgery to relieve the compression of the spinal cord by MTCDH. It avoids the fusion of the vertebral body for internal fixation, preserves the vertebral motion segments, avoids medical destruction of the cervical disc to the greatest extent possible, and expands the scope of adaptation of full endoscopic technology in cervical surgery.

Landform and lithospheric development contribute to the assembly of mountain floras in China.

Although it is well documented that mountains tend to exhibit high biodiversity, how geological processes affect the assemblage of montane floras is a matter of ongoing research. Here, we explore landform-specific differences among montane floras based on a dataset comprising 17,576 angiosperm species representing 140 Chinese mountain floras, which we define as the collection of all angiosperm species growing on a specific mountain. Our results show that igneous bedrock (granitic and karst-granitic landforms) is correlated with higher species richness and phylogenetic overdispersion, while the opposite is true for sedimentary bedrock (karst, Danxia, and desert landforms), which is correlated with phylogenetic clustering. Furthermore, we show that landform type was the primary determinant of the assembly of evolutionarily older species within floras, while climate was a greater determinant for younger species. Our study indicates that landform type not only affects montane species richness, but also contributes to the composition of montane floras. To explain the assembly and differentiation of mountain floras, we propose the 'floristic geo-lithology hypothesis', which highlights the role of bedrock and landform processes in montane floristic assembly and provides insights for future research on speciation, migration, and biodiversity in montane regions.