How to Set Working Cannula in Endoscopic-Assisted Transforaminal Lumbar Interbody Fusion: A Morphometric Analysis Based on Computed Tomography.

OBJECTIVES: There is a high risk of nerve root injury during endoscopic-assisted transforaminal lumbar interbody fusion (Endo-TLIF). This study used computed tomography (CT) imaging to assess the relationship between the exiting nerve root and its surroundings, and the corresponding intervertebral disc. We also measured the approximate position and angle for the placement of the working cannula to reduce the risk of nerve root injury during Endo-TLIF procedures in the Chinese population. METHODS: This retrospective study was conducted at our institution between December 2021 and December 2022. A total of 115 patients suffering from low back pain were recruited for the study. For each participant, three-dimensional (3D) vertebral models of the lumbar segments from L3 to S1 were constructed based on their CT images. The nerve root-disc distance, cannula insertion bypass distance and angle, foraminal height and width, exiting nerve root height, and nerve root-pedicle distance were measured. A paired t-test was used to compare measurements between the left and right sides, while inter- and intraobserver reproducibility was assessed using the intraclass correlation coefficient (ICC). RESULTS: From L3/4 to L5/S1 segments, the ideal cannula insertion distance range was 37.51 ± 4.91-120.38 ± 37.71 mm at L3/4; 42.38 ± 5.29-116.25 ± 27.22 mm at L4/5; and 37.78 ± 4.86-69.26 ± 12.64 mm at L5/S1. The appropriate cannula insertion angle range was 30.86° ± 5.05°-62.59° ± 6.66° at L3/4; 34.30° ± 4.73°-60.88° ± 7.34° at L4/5; and 35.89° ± 4.18°-47.65° ± 7.38° at L5/S1. The height of the intervertebral foramen (IVF) gradually decreased, and the width steadily increased. The exiting nerve root height and the nerve root-pedicle distance slightly decreased caudally. CONCLUSION: From L3/4 to L5/S1, the range of working cannula insertion distance and angle gradually decreased, and the exiting nerve root height occupying the IVF gradually increased. Our measurement can reduce the risk of nerve root injury caused by inserting the working cannula during Endo-TLIF.

[Study on related influencing factors on the occurrence of redundant sign in the cauda equina in lumbar spinal stenosis].

OBJECTIVE: To analyze the relational factors influencing the formation of cauda equina redundant nerve roots (RNRs) of the lumbar spinal stenosis. METHODS: Clinical data of 116 patients with lumbar spinal stenosis treated from January 2016 to June 2019 were retrospectively analyzed. The patients were divided into redundant nerve roots(RNRs) group and non-RNRs group based on the presence or absence of RNRs on sagittal T2-weighted MRI. In the non-RNRs group, there were 74 patients, including 38 males and 36 females with an average age of (62.00±10.41) years old, the body mass index (BMI) was (23.09±2.22) kg·m-2;the maximum stenosis segment was L2-L3 in 12 cases, L3-L4 in 38, L4-L5 in 20, and L5S1 in 4, respectively. In the RNRs group, there were 42 patients, including 18 males and 24 females with an average age of (63.36±8.73) years old, the BMI was (22.63±2.60) kg·m-2;the maximum stenosis segment was L2-L3 in 3 cases, L3-L4 in 9, L4-L5 in 27 and L5S1 in 3, respectively. MRI was performed in the supine position to observe the conshape and morphology of the redundant nerve in the sagittal position. The preoperative low back and leg pain visual analogue scale(VAS), and preoperative Oswestry disability index(ODI) were analyzed, and the rate of spondylolisthesis and ligamentum flavum hypertrophy were compared. Simultaneously, the inter-vertebral height, intervertebral foramen height, inter-vertebral height+vertebral height, median sagittal diameter at the inter-vertebral space level(DIW-MSD), median sagittal diameter at the pedicel level(DV-MSD), range of motion(ROM) of the stenotic segment were measured and analyzed. RESULTS: Among the 116 patients with lumbar spinal stenosis, 42 patients developed RNRs, with an incidence of 36.2%. There were no significant differences in gender, age, BMI, preoperative VAS for lumbar and leg pain and ODI between two groups(P>0.05). There were statistically significant differences regard to the duration of symptoms and the rate of spondylolisthesis and ligamentum flavum hypertrophy (P<0.05);the inter-vertebral height, intervertebral foramen height, inter-vertebral height+vertebral height, DIW-MSD, ROM of the stenotic segment were also significantly different between two groups(P<0.05). However, there was no significant difference in DV-MSD between two groups(P>0.05). CONCLUSION: The inter-vertebral height, inter-vertebral foramen height, inter-vertebral height+vertebral height, DIW-MSD and ROM of the stenotic segment were the crucial factors related to RNRs in lumbar spinal stenosis.

Classification of Osteophytes Occurring in the Lumbar Intervertebral Foramen.

BACKGROUND: Surgeons have limited knowledge of the lumbar intervertebral foramina. This study aimed to classify osteophytes in the lumbar intervertebral foramen and to determine their pathoanatomical characteristics, discuss their potential biomechanical effects, and contribute to developing surgical methods. METHODS: We conducted a retrospective, non-randomized, single-center study involving 1224 patients. The gender, age, and anatomical location of the osteophytes in the lumbar intervertebral foramina of the patients were recorded. RESULTS: Two hundred and forty-nine (20.34%) patients had one or more osteophytes in their lumbar 4 and 5 foramina. Of the 4896 foramina, 337 (6.88%) contained different types of osteophytes. Moreover, four anatomical types of osteophytes were found: mixed osteophytes in 181 (3.69%) foramina, osteophytes from the lower endplate of the superior vertebrae in 91 (1.85%) foramina, osteophytes from the junction of the pedicle and lamina of the upper vertebrae in 39 foramina (0.79%), and osteophytes from the upper endplate of the lower vertebrae in 26 (0.53%) foramina. The L4 foramen contained a significantly higher number of osteophytes than the L5 foramen. Osteophyte development increased significantly with age, with no difference between males and females. CONCLUSIONS: The findings show that osteophytic extrusions, which alter the natural anatomical structure of the lumbar intervertebral foramina, are common and can narrow the foramen.

Clinical efficacy and imaging analysis of oblique lateral lumbar interbody fusion in the treatment of different types of lumbar intervertebral foramen stenosis.

PURPOSE: To analyze and study the clinical efficacy and imaging indexes of oblique lateral lumbar interbody fusion (OLIF) in the treatment of lumbar intervertebral foramen stenosis(LFS) caused by different causes. METHOD: 33 patients with LFS treated with OLIF from January 2018 to May 2022 were reviewed. Oswestry Dysfunction Index (ODI) and visual analogue scale (VAS) were calculated before and after operation. Segmental lordotic angle (SLA), lumbar lordotic angle (LLA) and segmental scoliosis angle (SSA), disc height (DH), posterior disc height (PDH), lateral disc height (LDH), foraminal height (FH), foramen width (FW) and foraminal cross-sectional area (FSCA) were measured before and after operation. RESULT: The VAS and ODI after operation were significantly improved as compared with those before operation. Compared with pre-operation, the DH, PHD increased by 67.6%, 94.6%, LDH increased by 107.4% (left), 101.7% (right), and FH increased by 30.2% (left), 34.5% (right). The FSCA increased by 93.1% (left), 89.0% (right), and the FW increased by 137.0% (left), 149.6% (right). The postoperative SSA was corrected by 74.5%, the postoperative SLA, LLA were corrected by 70.2%, 38.1%, respectively. All the imaging indexes were significantly improved (p < 0.01). CONCLUSION: The clinical efficacy and imaging data of OLIF in the treatment of LFS caused by low and moderate lumbar spondylolisthesis, intervertebral disc bulge and reduced intervertebral space height, degenerative lumbar scoliosis, articular process hyperplasia or dislocation have been well improved. OLIF may be one of the better surgical treatments for LFS caused by the above conditions.

Spinal gout with intervertebral foramen infiltration: A rare case perfectly mimicking degenerative lumbar disc disease.

Spinal gout is a relatively rare disease characterized by significant clinical symptoms. In the current study, the first case of spinal gout with tophus in the intervertebral foramen, which perfectly mimicked degenerative lumbar disc disorders, was presented. The patient was a 57-year-old man with a medical history of gout who had suffered from progressive neurological deterioration for the last 12 months. Imaging examination revealed bilateral stenosis in the L5/S1 intervertebral foramen, mimicking degenerative lumbar disc disease. Nerve root radiculography and blocking were performed and the neurological symptoms were completely relieved. Open surgery was further performed and unexpectedly, the intra-operative findings were amorphous chalky white lesions. Histopathology confirmed the diagnosis of spinal gout. After surgery, the patient was prescribed a medication and achieved complete remission of clinical symptoms. No deterioration was found at the 1-year follow-up. To the best of our knowledge, this is the first report of spinal gout tophus in intervertebral foramen in the literature. It was concluded that, although intraspinal tophaceous gout is relatively rare, orthopedic surgeons should take it into consideration as a differential diagnosis, particularly if the patient has a medical history of gout. Early diagnosis and timely medical management may possibly be able to avoid neurological compromise and the need for surgery.

Comparative study of percutaneous endoscopic treatment of L5/S1 disc herniation by two approaches / 实用医学杂志

Objective To compare the efficacy of percutaneous transforaminal approach and translaminar approach in the treatment of L5/S1 disc herniation(LDH)under endoscopic discectomy.Methods Adopted a retro-spective case-control study,and selected 62 cases of patients with L5/S1 LDH who were treated with percutaneous endoscopic surgery in the spine surgery department of our hospital from June 2020 to December 2022,and the transforaminal approach was used.(TELD)in 32 cases(TELD group),and interlaminar approach(IELD)in 30 cases(IELD group).The observation indicators included intraoperative fluoroscopy times,operation time,hospitaliza-tion days,hospitalization expenses,leg pain VAS score,ODI score,modified MacNab curative effect evaluation and complications.Results All 62 patients successfully completed the operation and follow-up,and no serious complications occurred.There were statistically significant differences in operation time,fluoroscopy times,and hospitalization expenses between the two groups(P<0.001),but there was no significant difference in hospitaliza-tion days between the two groups(P>0.05).The lower extremity VAS scores at the last follow-up and the last follow-up were significantly improved compared with those before operation(P<0.001),and the ODI scores of the two groups were significantly improved at 2 days,1 month and at the last follow-up(P<0.001).At the same time point,there was no statistical difference(P>0.05);there was no significant difference in the excellent and good rate of surgery between the two groups(P>0.05).11 patients with high iliac crest in the TELD group successfully completed the surgery.Conclusions Both the endoscopic surgery through the intervertebral foramen and the inter-laminar approach can achieve satisfactory results in the treatment of L5/S1 LDH.However,local anesthesia through the intervertebral foramen approach reduces hospitalization costs,and patients with high iliac crest can successfully complete the surgery by selecting a suitable puncture path.The translaminar approach has fewer fluoroscopy times and shorter surgical time,but there is a higher risk of dura mater and nerve damage,which requires careful opera-tion for beginners.

A comparative study of the anatomy and MRI images of the lumbar foraminal ligaments at the L1-L5 levels.

PURPOSE: The purpose of this study was to evaluate the ability of MRI images to reveal foraminal ligaments at levels L1-L5 by comparing the results with those of anatomical studies. METHODS: Eighty lumbar foramina were studied. First, the best MRI scanning parameters were selected, and the transverse and sagittal axes of each lumbar foramina were scanned to identify and record the ligament-like structures in each lumbar foramen. Then, the cadaveric specimens were anatomically studied, and all ligament structures in the lumbar foramina were retained. The number, morphology and distribution of ligaments under anatomical and MRI scanning were observed. Histological staining of the dissected ligament structures was performed to confirm that they were ligamentous tissues. Finally, the accuracy of ligament recognition in MRI images was statistically analyzed. RESULTS: A total of 233 foraminal ligaments were identified in 80 lumbar intervertebral foramina through cadaveric anatomy. The radiating ligaments (176, 75.5%) were found to be attached from the nerve root to the surrounding osseous structures, while the transforaminal ligaments (57, 24.5%) traversed the intervertebral foramina without any connection to the nerve roots. A total of 42 transforaminal ligament signals and 100 radiating ligament signals were detected in the MRI images of the 80 intervertebral foramina. CONCLUSION: The MRI can identify the lumbar foraminal ligament, and the recognition rate of the transforaminal ligament is higher than that of the radiating ligament. This study provides a new method for the clinical diagnosis of the relationship between the lumbar foraminal ligament and radicular pain.

Effect of preoperative contralateral foramen stenosis on contralateral root symptoms after unilateral transforaminal lumbar interbody fusion: a ambispective cohort study.

PURPOSE: To evaluate the correlation between the degree of preoperative contralateral foraminal stenosis(CFS) and the incidence of contralateral root symptoms after unilateral transforaminal lumbar interbody fusion(TLIF) and to evaluate the appropriate candidate of preventive decompression according to the degree of preoperative contralateral foraminal stenosis. METHODS: An ambispective cohort study was conducted to investigate the incidence of contralateral root symptoms after unilateral transforaminal lumbar interbody fusion (TLIF) and the effectiveness of preventive decompression. A total of 411 patients were included in the study, all of whom met the inclusion and exclusion criteria and underwent surgery at the Department of Spinal Surgery, Ningbo Sixth Hospital, between January 2017 and February 2021. The study was divided into two groups: retrospective cohort study A and prospective cohort study B. The 187 patients included in study A from January 2017 to January 2019 did not receive preventive decompression. They were divided into four groups based on the degree of preoperative contralateral intervertebral foramen stenosis: no stenosis group A1, mild stenosis group A2, moderate stenosis group A3, and severe stenosis group A4. A Spearman rank correlation analysis was used to evaluate the correlation between the preoperative contralateral foramen stenosis degree and the incidence of contralateral root symptoms after unilateral TLIF. From February 2019 to February 2021, 224 patients were included in the prospective cohort group B. The decision to perform preventive decompression during the operation was based on the degree of preoperative contralateral foramen stenosis. Severe intervertebral foramen stenosis was treated with preventive decompression as group B1, while the rest were not treated with preventive decompression as group B2. The baseline data, surgical-related indicators, the incidence of contralateral root symptoms, clinical efficacy, imaging results, and other complications were compared between group A4 and group B1. RESULTS: All 411 patients completed the operation and were followed up for an average of 13.5 ± 2.8 months. In the retrospective study, there was no significant difference in baseline data among the four groups (P > 0.05). The incidence of postoperative contralateral root symptoms increased gradually, and a weak positive correlation was found between the degree of preoperative intervertebral foramen stenosis and the incidence of postoperative root symptoms (rs = 0.304, P < 0.001). In the prospective study, there was no significant difference in baseline data between the two groups. The operation time and blood loss in group A4 were less than those in group B1 (P < 0.05). The incidence of contralateral root symptoms in group A4 was higher than that in group B1 (P = 0.003). However, there was no significant difference in leg VAS score and ODI index between the two groups at 3 months after the operation (P > 0.05). There was no significant difference in cage position, intervertebral fusion rate, and lumbar stability between the two groups (P > 0.05). No incisional infection occurred after the operation. No pedicle screw loosening, displacement, fracture, or interbody fusion cage displacement occurred during follow-up. CONCLUSION: This study found a weak positive correlation between the degree of preoperative contralateral foramen stenosis and the incidence of contralateral root symptoms after unilateral TLIF. Intraoperative preventive decompression of the contralateral side may prolong the operation time and increase intraoperative blood loss to some extent. However, when the contralateral intervertebral foramen stenosis reaches the severe level, it is recommended to perform preventive decompression during the operation. This approach can reduce the incidence of postoperative contralateral root symptoms while ensuring clinical efficacy.

Paravertebral Cerebrospinal Fluid Exudation in Young Women with Postdural Puncture Headache: A Hypothetical Interpretation based on Anatomical Study on Intervertebral Foramen.

Background Postdural puncture headache (PDPH) is defined as a prolonged orthostatic headache secondary to a lumbar puncture. The mechanism underlying this unpleasant complication and the reasons explaining its higher incidence in the young are not well understood. Here, we speculate on the mechanisms underlying PDPH based on spinal magnetic resonance imaging (MRI) in patients with PDPH and an anatomical study on the size of the intervertebral foramen. Methods Brain and spinal MRI findings were examined in two young women with PDPH. The relationship between age and size of the intervertebral foramen on computed tomography was assessed in 25 female volunteers (22-89 years old) without spinal disease. Results The causative interventions leading to PDPH were epidural anesthesia for painless delivery in a 28-year-old woman and lumbar puncture for examination of the cerebrospinal fluid (CSF) in a 17-year-old woman. These two patients developed severe orthostatic hypotension following the procedure. Brain MRI showed signs of intracranial hypotension, including subdural effusion, in one patient, but no abnormality in the other. Spinal MRI revealed an anterior shift of the spinal cord at the thoracic level and CSF exudation into the paravertebral space at the lumbar level. Treatment involving an epidural blood patch in one patient and strict bed rest with sufficient hydration in the second led to improvement of symptoms and reduction of paravertebral CSF exudation. The size of the intervertebral foramen at the L2-3 level in the 25 volunteers showed a decrease in an age-dependent manner (Spearman's rho -0.8751, p < 0.001). Conclusion We suggest that CSF exudation from the epidural space of the vertebral canal to the paravertebral space through the intervertebral foramen, which is generally larger in the younger population, is the causative mechanism of PDPH.

Specific foraminal changes originate from degenerative spondylolisthesis on computed tomographic images.

PURPOSE: Operative treatment for degenerative spondylolisthesis (DS) is accompanied by the high incidence of nerve injury. Foraminal structures, especially the hypertrophied facet joints, have significant impacts on the adjacent nerve. This study aims to identify the specific foraminal changes relating to DS and nerve injury. METHODS: The CT images of 70 patients with DS and 50 patients without lumbar disease were collected. The length and height of the foraminal structure were measured horizontally and vertically on sagittally reconstructed images. Horizontal stenosis, meaning to pending compression to nerve root after complete reduction, was evaluated on the image located to the middle of the foramen. Chi-square test or T-test were carried out using SPSS 26.0. RESULTS: The hyperplasia of the superior articular process (SAP) and articular capsule (Ac) incidence rates in DS group was significantly more common than that of the control group (9.2 vs 0.0%, 42.9 vs 2.0%). The height and width of the SAP and Ac in vertical and horizontal directions were significantly greater than those in the control group (4.95 mm vs - 0.47 mm, P < 0.0001; 3.28 vs 0.02 mm, P < 0.0001; 5.27 vs3.44 mm, P < 0.0001; 2.60 vs 0.37 mm, P < 0.0001). In the DS group, hyperplasia of the SAP and Ac accounted for 9 and 43% respectively, 85 and 45% of which were accompanied by horizontal stenosis of the intervertebral foramen. CONCLUSION: DS is usually characterized of excessive hyperplasia of the SAP and Ac, both of which are possible elements of nerve root injury after complete reduction in operation and should be focused on during surgery.

Endoscopic Revision for Long-Term Symptomatic Cage Retropulsion after TLIF: The Clinical Presentation in a Single Center.

BACKGROUND: Cage retropulsion after transforaminal lumbar interbody fusion (TLIF) is a common complication that is more frequently detected in the early postoperative period. Revision in the early stages is relatively less difficult in symptomatic cases. However, cage retropulsion is quite rare for patients with intervertebral osseous fusion in the long term after TLIF, and there are no relevant reports related to the revision plan. CASE PRESENTATION: Here, we report a case of a patient who underwent L4-S1 TLIF at another hospital 4 years ago, accompanied by recurrent pain and discomfort of the left lower limb after the operation. Due to recent condition aggravation, it was considered to be caused by compression of the nerve root due to cage retropulsion. Nerve root sealing and endoscopy surgery were performed on the operative segment. It was found that cage retropulsion at the L4/5 level was a suspicious focus according to careful analysis of the clinical manifestations of the patient. Selective block of the nerve root on the level resulted in relief of the patient's original symptoms. After the posterior edge of the cage was exposed under the endoscope through an intervertebral foramen approach, the posterior edge of the cage protruding into the spinal canal was removed by high-speed burr grinding, working casing reduction and other methods. Postoperative symptoms of pain in the low back and lower limb were relieved completely. CONCLUSIONS: It is feasible to use the power system to remove the retrograde cage under the endoscope through the intervertebral foramen approach for the revision of symptomatic polyether ether ketone (PEEK) cage retropulsion in the long term after TLIF.

[Percutaneous foraminal endoscopy for the treatment of lumbar lateral recess stenosis in elderly].

OBJECTIVE: To investigate the clinical efficacy and safety of percutaneous foraminal endoscopy in the treatment of lumbar lateral recess stenosis in elderly. METHODS: The clinical data of 31 elderly patients with lumbar lateral recess stenosis treated by percutaneous foraminal endoscopic decompression from March 2018 to August 2019 were retrospectively analyzed. Including 16 males and 15 females, aged from 65 to 81 years with an average of (71.13±5.20) years, the course of disease ranged from 3 months to 7 years with an average of (14.36±6.52) months. Visual analogue scale (VAS) and Oswestry disability index (ODI) were used to assess clinical symptom and functional status before operation and 1, 6, 12 months after operation. At the final follow-up, the modified Macnab standard was used to evaluate clinical efficacy. RESULTS: All patients were completed the operation successfully. The operation time was from 75 to 120 min with an average of (97.84±11.22 ) min. All 31 patients were followed up from 12 to 28 months with an average of (17.29±5.56) months. Postoperative lumbago-leg pain VAS and ODI were significantly improved at 1, 6, and 12 months(P<0.01). At the final follow-up, according to the modified Macnab standard to evaluate the effect, 23 got excellent results, 5 good, 3 fair. One patient had severe adhesions between peripheral tissues and nerve root, and postoperative sensory abnormalities in the lower extremities were treated conservatively with traditional Chinese medicine and neurotrophic drugs, which recovered at 2 weeks after surgery. No complications such as nerve root injury and infection occurred. CONCLUSION: The intervertebral foraminal endoscopy technique, which is performed under local anesthesia for a short period of operation, ensures adequate decompression while minimizing complications, and is a safe and effective surgical procedure for elderly patients with lumbar lateral recess stenosis.

Predictive Effect of Intervertebral Foramen Width on Pain Relief After ACDF for the Treatment of Cervical Radiculopathy.

STUDY DESIGN: Retrospective cohort study. OBJECTIVE: To investigate the relationship between the preoperative width of the intervertebral foramen (WIVF) and the pain relief in patients who underwent anterior cervical discectomy and fusion (ACDF) for the treatment of cervical radiculopathy. METHODS: Patients were divided into 2 groups based on pain relief status at the 6-month follow-up (pain relief group: 430 patients; persistent pain group: 108 patients). Possible factors such as age, sex, body mass index (BMI), the symptom duration, the preoperative Japanese Orthopedic Association (JOA) scores, the canal stenosis status, and the graft material were obtained. The C2-C7 Cobb angle, disc space, and width and height of the intervertebral foramen were measured on X-ray and CT 3-dimension reconstruction. Multivariate logistic regression was performed to identify the factors that affected pain relief. A receiver operating characteristic (ROC) curve was drawn for the predictive factors to determine the optimal threshold for foreseeing persistent pain. RESULTS: There were significant differences in the preoperative WIVF, symptom duration and ratio of disc space distraction between the 2 groups (each P < 0.05). The regression model showed that pain relief was negatively affected by the symptom duration and ratio of disc space distraction. Besides, an increase in the preoperative width of the intervertebral foramen (WIVF) could significantly decrease the possibility of persistent pain. Based on the ROC curve, the optimal threshold of preoperative WIVF was 4.35 mm. CONCLUSION: When the preoperative WIVF is equal to or less than 4.35 mm, the possibility of the occurrence of postoperative persistent pain significantly increased.

"Inside Disc Out" Discectomy for the Treatment of Discogenic Lumbar Spinal Canal Stenosis under the Intervertebral Foramen Endoscope.

OBJECTIVE: Conventional posterior-approach decompression surgeries have a higher risk of nerve root injury and dura laceration. We explore the therapeutic strategy and effect of "inside disc out" discectomy under intervertebral foramen endoscope technique for discogenic lumbar spinal canal stenosis (DLSS) treatment. METHODS: Twenty-nine patients with DLSS in the responsible segment were treated with "inside disc out" discectomy under intervertebral foramen endoscope technique between October 2017 to October 2019. Lower limb and back pain were recorded before operation, and visual analogue scale (VAS) score and Oswestry disability index (ODI) were recorded for lower limb and back pain at 1, 3, 6, and 12 months postoperatively. The postoperative effects were evaluated using the modified MacNab method for all the patients. RESULTS: All 29 patients successfully completed the operation. The operation time was 75-120 min, with an average of 90 ± 17 min. Postoperative lumbar CT examinations of all the patients showed full decompression of the spinal cord with no residual pressure. The average follow-up time for all the patients was 13 ± 3.5 months (12-18 months). The VAS score for lower back and lower limb pain was 7.52 ± 1.25 before the operation, and 1.80 ± 0.63, 1.33 ± 0.88, 1.07 ± 0.89, and 0.81 ± 0.51 at 1, 3, 6, and 12 months after the surgery, respectively. The Oswestry dysfunction index was 59.43 ± 10.04 before surgery and 29.67 ± 10.35, 21.13 ± 9.32, 14.52 ± 5.98, and 9.84 ± 4.68 at 1, 3, 6, and 12 months after the surgery, respectively. The VAS score and ODI index of low back and lower limb pain at different time points after the surgery were significantly improved compared to those before the surgery (P < 0.01). The effect of the modified MacNab was excellent in 26 patients, good in two patients, and fair in one patient. The excellent and good rates were 91.4%. Among them, one patient had symptoms of hyperesthesia in the anterior aspect of the thigh and decreased quadriceps muscle strength after lumbar 4/5 segment endoscopic surgery. After symptomatic and conservative treatment, the symptoms disappeared 4 weeks postoperatively, and there were no other serious surgical complications. CONCLUSIONS: Following the "inside disc out" discectomy under intervertebral foramen endoscope protocols, the risk of nerve injury can greatly be reduced, with good postoperative efficacy. Overall, the procedure is safe and feasible for DLSS treatment.

Changes in the lumbar intervertebral foramen between supine and standing posture in patients with adult spinal deformity: a study with upright computed tomography.

OBJECTIVE: To quantitatively assess the impact of supine and standing positions on the morphological changes in the lumbar intervertebral foramen (LIF) in patients with adult spinal deformity (ASD) using upright CT and conventional supine CT. MATERIALS AND METHODS: Thirty patients with ASD were prospectively enrolled in this study. All subjects underwent standing whole spine posterior/anterior radiographs, lateral radiographs, and whole spine CT, both in the supine and upright standing positions. Two orthopedic surgeons independently measured nine radiographic parameters in the radiograph and the lumbar foraminal area (FA) and height (FH) in supine and upright CT. Statistical analyses were performed to evaluate the risk of LIF decrease when standing upright compared to the supine position. The chi-squared, t test, Pearson's coefficients, intra- and inter-rater reliabilities, and ROC curves were calculated. The level of significance was set at p < 0.05. RESULTS: Among the 300 LIFs, both the lumbar FA and FH were either increased or decreased by > 5% in approximately 30% of LIFs each. The FA decreased in the lower lumbar spine. The concave side had a significantly higher rate of decreased FA and FH than the convex side (p < 0.05 and < 0.05, respectively). ROC analysis showed that narrowing of the intervertebral disc (cutoff > 0.05°) is a risk factor for decreased FA and FH. CONCLUSIONS: This study describes the details of the changes in the neuroforamen using a novel upright CT. In patients with ASD, approximately 30% of LIFs either increased or decreased in size by > 5% when standing. The risk factors for LIF decrease are the lower lumbar spine, concave side, and narrow side of the disc wedge.

Percutaneous foraminal endoscopy for the treatment of lumbar lateral recess stenosis in elderly / 中国骨伤

OBJECTIVE@#To investigate the clinical efficacy and safety of percutaneous foraminal endoscopy in the treatment of lumbar lateral recess stenosis in elderly.@*METHODS@#The clinical data of 31 elderly patients with lumbar lateral recess stenosis treated by percutaneous foraminal endoscopic decompression from March 2018 to August 2019 were retrospectively analyzed. Including 16 males and 15 females, aged from 65 to 81 years with an average of (71.13±5.20) years, the course of disease ranged from 3 months to 7 years with an average of (14.36±6.52) months. Visual analogue scale (VAS) and Oswestry disability index (ODI) were used to assess clinical symptom and functional status before operation and 1, 6, 12 months after operation. At the final follow-up, the modified Macnab standard was used to evaluate clinical efficacy.@*RESULTS@#All patients were completed the operation successfully. The operation time was from 75 to 120 min with an average of (97.84±11.22 ) min. All 31 patients were followed up from 12 to 28 months with an average of (17.29±5.56) months. Postoperative lumbago-leg pain VAS and ODI were significantly improved at 1, 6, and 12 months(P<0.01). At the final follow-up, according to the modified Macnab standard to evaluate the effect, 23 got excellent results, 5 good, 3 fair. One patient had severe adhesions between peripheral tissues and nerve root, and postoperative sensory abnormalities in the lower extremities were treated conservatively with traditional Chinese medicine and neurotrophic drugs, which recovered at 2 weeks after surgery. No complications such as nerve root injury and infection occurred.@*CONCLUSION@#The intervertebral foraminal endoscopy technique, which is performed under local anesthesia for a short period of operation, ensures adequate decompression while minimizing complications, and is a safe and effective surgical procedure for elderly patients with lumbar lateral recess stenosis.

Limitations of minimally invasive posterior cervical foraminotomy-a decompression method of posteriorly shifting the nerve root-in cases of large anterior osteophytes in cervical radiculopathy: A retrospective multicenter cohort study.

BACKGROUND: Posterior cervical foraminotomy against anterior osteophyte is an indirect decompression procedure but less invasive compared to anterior cervical discectomy and fusion. Residual compression to the nerve root may lead to poor surgical outcomes. Although clinical results of posterior cervical foraminotomy for osteophytes are not considered better than those of disk herniation, osteophyte size and the association of the decompression area with poor surgical outcomes remain unclear. This study aimed to identify the limitations of minimally invasive posterior cervical foraminotomy for cervical radiculopathy and discuss the methods to improve surgical outcomes. METHODS: We analyzed 55 consecutive patients with degenerative cervical radiculopathy who underwent minimally invasive posterior cervical foraminotomy. Minimum postoperative follow-up duration was 1 year. We divided the patients into nonimproved and improved groups. The cutoff value between preoperative and postoperative Neck Disability Index scores was 30% improvement. Preoperative imaging data comprised disk height, local kyphosis, spinal cord compression, anterior osteophytes in the foramen, and anterior osteophytes of >50% of the intervertebral foramen diameter. Postoperative imaging data comprised craniocaudal length and lateral width of decompressed lamina, preserved superior facet width, and area of decompressed lamina. RESULTS: Fifty-five patients were divided into two groups: nonimproved (n = 19) and improved (n = 36). The presence of osteophytes itself was not significant; however, the presence of osteophytes of >50% of the foramen diameter increased in the nonimproved group (P = 0.004). Mean lateral width and mean area of decompressed lamina after surgery significantly increased in the improved group (P = 0.001, P = 0.03). CONCLUSION: The presence of anterior osteophytes >50% of the diameter of the foramen led to poor improvement of clinical outcomes in minimally invasive posterior cervical foraminotomy. However, the larger the lateral width and area of the decompressed lamina, the better the surgical outcome.

Correlation between C7-T1 Intervertebral Foramen Area and Sagittal Parameters in Patients with Cervical Spondylotic Myelopathy.

OBJECTIVE: Cervical spondylotic myelopathy (CSM) is an incomplete spinal cord injury characterized with pain and stiffness in the neck and motor and sensory dysfunction. This study aims to determine whether C7-T1 intervertebral foramen area could be used as a parameter to evaluate the sagittal curvature of cervical spine. METHODS: Patients with clinical manifestations of spinal cord compression were hospitalized in our hospital from September 2018 to August 2019. All patients were diagnosed with CSM by nuclear magnetic imaging and other imaging methods. C2-C7 Cobb angle and T1 slop (T1S) were measured on the sagittal, T2-weighted magnetic resonance image of cervical spine, and C7-T1 intervertebral foramen area were measured using oblique cervical spine X-rays. Patients were divided into two groups according to the value of C2-C7 Cobb angle, including lordosis group (C2-C7 Cobb angle >10°, n = 45) and straight group (C2-7 Cobb angle ≤10°, n = 55). The reliability of the data was evaluated by intraclass correlation coefficient (ICC), and the correlation of the imaging parameters was analyzed by Pearson correlation. RESULTS: A total of 100 patients diagnosed with CSM hospitalized in our department were included. The ICC of the cervical parameters was 0.73. C7-T1 intervertebral foramen area was 40.69 ± 11.44 and 39.95 ± 10.94 mm2 in lordosis and straight group, respectively. The results showed that C7-T1 intervertebral foramen area was positively correlated with both C2-C7 Cobb angle (r = 0.23, p = 0.02) and T1S (r = 0.21, p = 0.03). In lordosis group, there was a positive correlation between C7 and T1 intervertebral foramen area and C2-C7 Cobb angle (r = 0.69, p < 0.01) and T1S (r = 0.34, p = 0.02). However, in straight group, C7-T1 intervertebral foramen area was not correlated with either C2-C7 Cobb angle or T1S. CONCLUSION: C7-T1 intervertebral foramen area measured by oblique X-ray could be an effective method to evaluate the sagittal balance of cervical vertebrae for CSM patients with cervical lordosis.

Automated Magnetic Resonance Image Segmentation of Spinal Structures at the L4-5 Level with Deep Learning: 3D Reconstruction of Lumbar Intervertebral Foramen.

OBJECTIVE: 3D reconstruction of lumbar intervertebral foramen (LIVF) has been beneficial in evaluating surgical trajectory. Still, the current methods of reconstructing the 3D LIVF model are mainly based on manual segmentation, which is laborious and time-consuming. This study aims to explore the feasibility of automatically segmenting lumbar spinal structures and increasing the speed and accuracy of 3D lumbar intervertebral foramen (LIVF) reconstruction on magnetic resonance image (MRI) at the L4-5 level. METHODS: A total of 100 participants (mean age: 42.2 ± 14.0 years; 52 males and 48 females; mean body mass index, 22.7 ± 3.2 kg/m2 ), were enrolled in this prospective study between March and July 2020. All participants were scanned on L4-5 level with a 3T MR unit using 3D T2-weighted sampling perfection with application-optimized contrast with various flip-angle evolutions (SPACE) sequences. The lumbar spine's vertebra bone structures (VBS) and intervertebral discs (IVD) were manually segmented by skilled surgeons according to their anatomical outlines from MRI. Then all manual segmentation were saved and used for training. An automated segmentation method based on a 3D U-shaped architecture network (3D-UNet) was introduced for the automated segmentation of lumbar spinal structures. A number of quantitative metrics, including dice similarity coefficient (DSC), precision, and recall, were used to evaluate the performance of the automated segmentation method on MRI. Wilcoxon signed-rank test was applied to compare morphometric parameters, including foraminal area, height and width of 3D LIVF models between automatic and manual segmentation. The intra-class correlation coefficient was used to assess the test-retest reliability and inter-observer reliability of multiple measurements for these morphometric parameters of 3D LIVF models. RESULTS: The automatic segmentation performance of all spinal structures (VBS and IVD) was found to be 0.918 (healthy levels: 0.922; unhealthy levels: 0.916) for the mean DSC, 0.922 (healthy levels: 0.927; unhealthy levels: 0.920) for the mean precision, and 0.917 (healthy levels: 0.918; unhealthy levels: 0.917) for the mean recall in the test dataset. It took approximately 2.5 s to achieve each automated segmentation, far less than the 240 min for manual segmentation. Furthermore, no significant differences were observed in the foraminal area, height and width of the 3D LIVF models between manual and automatic segmentation images (P > 0.05). CONCLUSION: A method of automated MRI segmentation based on deep learning algorithms was capable of rapidly generating accurate segmentation of spinal structures and can be used to construct 3D LIVF models from MRI at the L4-5 level.