[Short-term effectiveness of unilateral biportal endoscopy technique in treatment of lumbar lateral saphenous fossa combined with intervertebral foramina stenosis via contralateral sublaminar approach].

Objective: To investigate the short-term effectiveness of unilateral biportal endoscopy (UBE) in treatment of lumbar lateral saphenous fossa combined with intervertebral foramina stenosis via contralateral sublaminar approach. Methods: A clinical data of 15 patients with lumbar lateral saphenous fossa combined with intervertebral foramina stenosis, who were admitted between September 2021 and December 2023 and met selective criteria, was retrospectively analyzed. There were 5 males and 10 females with an average age of 70.3 years (range, 46-83 years). Surgical segment was L 4, 5 in 12 cases and L 5, S 1 in 3 cases. The disease duration was 12-30 months (mean, 18.7 months). All patients were treated by UBE via contralateral sublaminar approach. The operation time, intraoperative blood loss, postoperative hospital stay, and the occurrence of complications were recorded. The visual analogue scale (VAS) score was used to evaluate the degree of lower back and leg pain before and after operation; the Japanese Orthopaedic Association (JOA) score and the Oswestry disability index (ODI) were used to evaluate the lumbar function; and the clinical outcome was evaluated using the MacNab criteria at 6 months after operation. Postoperative MRI and CT were taken to observe whether the lateral saphenous fossa and intervertebral foramen stenosis were removed or not, and the cross-sectional area of the spinal canal (CSA-SC), cross-sectional area of the intervertebral foramen (CSA-IVF), and cross-sectional area of the facet joint (CSA-FJ) were measured. Results: The operation time was 55-200 minutes (mean, 127.5 minutes); the intraoperative blood loss was 10-50 mL (mean, 27.3 mL); the length of postoperative hospital stay was 3-12 days (mean, 6.8 days). All patients were followed up 6-12 months (mean, 8.9 months). At 1 day, 1 month, 3 months, and 6 months after operation, the VAS scores of low back and leg pain and ODI scores after operation were significantly lower than preoperative scores and showed a gradual decrease with time; the JOA scores showed a gradual increase with time; the differences in the above indexes between different time points were significant ( P<0.05). The clinical outcome was rated as excellent in 10 cases, good in 4 cases, and poor in 1 case according to the MacNab criteria at 6 months after operation, with an excellent and good rate of 93.33%. Imaging review showed that the compression on the lateral saphenous fossa and intervertebral foramina had been significantly relieved, and the affected articular process joint was preserved to the maximum extent; the CSA-SC and CSA-IVF at 3 days after operation significantly increased compared to the preoperative values ( P<0.05), and the CSA-FJ significantly reduced ( P<0.05). Conclusion: The UBE via contralateral sublaminar approach can effectively reduce pressure in the lateral saphenous fossa and the intervertebral foramina of the same segment while preserving the bilateral articular process joints. The short-term effectiveness is good and it is expected to avoid fusion surgery caused by iatrogenic instability of the lumbar spine. However, further follow-up is needed to clarify the mid- and long-term effectiveness.

Differences in MRI measurements of lateral recesses and foramina in degenerative lumbar segments in upright versus decubitus symptomatic patients.

OBJECTIVE: To evaluate differences in measurements of the lateral recesses and foramina in degenerative lumbar segments on MR images in symptomatic patients obtained with the patient standing versus lying down and to analyze the relationship between possible differences and patients' symptoms. MATERIAL AND METHODS: We studied 207 disc levels in 175 patients aged between 17 and 75 years (median: 47 years) with low back pain. All patients underwent MRI in the decubitus position with their legs extended, followed by MRI in the standing position. We calculated the difference in the measurements of the lateral recesses (in mm) and in the foramina (area in mm2 and smallest diameter in mm) obtained in the two positions. To eliminate the effects of possible errors in measurement, we selected cases in which the difference between the measurements obtained in the two positions was ≥10%; we used Student's t-tests for paired samples to analyze the entire group and subgroups of patients according to age, sex, grade of disc degeneration, and postural predominance of symptoms. RESULTS: Overall, the measurements of the spaces were lower when patients were standing. For the lateral recesses, we observed differences ≥10% in 68 (33%) right recesses and in 65 (31.5%) left recesses; when patients were standing, decreases were much more common than increases (26% vs. 7%, respectively, on the right side and 24% vs. 7.5%, respectively, on the left side; p < 0.005). For the foramina, decreases in both the area and in the smallest diameter were also more common than increases when patients were standing: on the right side, areas decreased in 23% and increased in 4%, and smallest diameters decreased in 20% and increased 6%; on the left side, areas decreased in 24% and increased in 4%, and smallest diameters decreased in 17% and increased in 8% (p < 0.005). Considering the group of patients in whom the postural predominance of symptoms was known, we found significant differences in patients whose symptoms occurred predominantly or exclusively when standing, but not in the small group of patients whose symptoms occurred predominantly while lying. We found no differences between sexes in the changes in measurements of the recesses or foramina with standing. The differences between the measurements obtained in different positions were significant in patients aged >40 years, but not in younger groups of patients. Differences in relation to the grade of disc degeneration were significant only in intermediate grades (groups 3-6 in the Griffith classification system). CONCLUSION: MRI obtained with patients standing can show decreases in the lateral recesses and foramina related to the predominance of symptoms while standing, especially in patients aged >40 years with Griffith disc degeneration grade 3-6, thus providing additional information in the study of patients who have low back pain when standing in whom the findings on conventional studies are inconclusive or discrepant with their symptoms. Further studies are necessary to help better define the value of upright MRI studies for degenerative lumbar disease.

Anatomical Evaluation of Spinal Nerve and Cervical Intervertebral Foramina in Anterior Controllable Antedisplacement and Fusion Surgery: A Cadaveric and Radiologic Study.

OBJECTIVE: To achieve the anatomical evaluation of spinal nerve and cervical intervertebral foramina in anterior controllable antedisplacement and fusion (ACAF) surgery, a novel surgical technique with the wider decompression, through a cadaveric and radiologic study. METHODS: Radiographic data of consecutive 47 patients (21 by ACAF and 26 by anterior cervical corpectomy and fusion [ACCF]) who have accepted surgery for treatment of cervical ossification of the posterior longitudinal ligament(OPLL) and stenosis from March 2017 to March 2018 were retrospectively reviewed and compared between an ACAF group and ACCF group. Three postoperative radiographic parameters were evaluated: the decompression width and the satisfaction rate of decompression at the entrance zone of intervertebral foramina on computed tomography (CT), and the transverse diameter of spinal cord in the decompression levels on magnetic resonance imaging (MRI). In the anatomic study, three fresh cadaveric spines (death within 3 months) undergoing ACAF surgery were also studied. Four anatomic parameters were evaluated: the width of groove, the distance between the bilateral origins of ventral rootlets, the length of ventral rootlet from their origin to the intervertebral foramina, the descending angle of ventral rootlet. RESULTS: The groove created in ACAF surgery included the bilateral origins of ventral rootlets. The rootlets tended to be vertical from the rostral to the caudal direction as their takeoff points from the central thecal sac became higher and farther away from their corresponding intervertebral foramina gradually. No differences were identified between left and right in terms of the length of ventral rootlet from the origin to the intervertebral foramina and the descending angle of ventral rootlet. The decompression width was significantly greater in ACAF group (19.2 ± 1.2 vs 14.7 ± 1.2, 21.3 ± 2.2 vs 15.4 ± 0.9, 21.5 ± 2.1 vs 15.7 ± 1.0, 21.9 ± 1.6 vs 15.9 ± 0.8, from C3 to C6 ). The satisfactory rate of decompression at the entrance zone of intervertebral foramina tended to be better in the left side in ACAF group (significant differences were identified in the left side at C3/4 , C4/5 , C6/7 level, and in the right side at C4/5 level when compared with ACCF). And decompression width was significantly greater than the transverse diameter of spinal cord in ACAF group. Comparatively, there existed no significant difference in the ACCF group besides the C5 level. CONCLUSION: ACAF can decompress the entrance zone of intervertebral foramina effectively and its decompression width includes the origins and massive running part of bilateral ventral rootlets. Due to its wider decompression range, ACAF can be used as a revision strategy for the patients with failed ACCF.

Differences in MRI measurements of lateral recesses and foramina in degenerative lumbar segments in upright versus decubitus symptomatic patients. / Cambios en recesos laterales y forámenes en segmentos degenerativos lumbares de pacientes sintomáticos estudiados mediante resonancia magnética en decúbito y bipedestación.

OBJECTIVE: To evaluate differences in measurements of the lateral recesses and foramina in degenerative lumbar segments on MR images in symptomatic patients obtained with the patient standing versus lying down and to analyze the relationship between possible differences and patients' symptoms. MATERIAL AND METHODS: We studied 207 disc levels in 175 patients aged between 17 and 75 years (median: 47 years) with low back pain. All patients underwent MRI in the decubitus position with their legs extended, followed by MRI in the standing position. We calculated the difference in the measurements of the lateral recesses (in mm) and in the foramina (area in mm2 and smallest diameter in mm) obtained in the two positions. To eliminate the effects of possible errors in measurement, we selected cases in which the difference between the measurements obtained in the two positions was ≥10%; we used Student's t-tests for paired samples to analyze the entire group and subgroups of patients according to age, sex, grade of disc degeneration, and postural predominance of symptoms. RESULTS: Overall, the measurements of the spaces were lower when patients were standing. For the lateral recesses, we observed differences ≥10% in 68 (33%) right recesses and in 65 (31.5%) left recesses; when patients were standing, decreases were much more common than increases (26% vs. 7%, respectively, on the right side and 24% vs. 7.5%, respectively, on the left side; p<0.005). For the foramina, decreases in both the area and in the smallest diameter were also more common than increases when patients were standing: on the right side, areas decreased in 23% and increased in 4%, and smallest diameters decreased in 20% and increased 6%; on the left side, areas decreased in 24% and increased in 4%, and smallest diameters decreased in 17% and increased in 8% (p<0.005). Considering the group of patients in whom the postural predominance of symptoms was known, we found significant differences in patients whose symptoms occurred predominantly or exclusively when standing, but not in the small group of patients whose symptoms occurred predominantly while lying. We found no differences between sexes in the changes in measurements of the recesses or foramina with standing. The differences between the measurements obtained in different positions were significant in patients aged>40 years, but not in younger groups of patients. Differences in relation to the grade of disc degeneration were significant only in intermediate grades (groups 3-6 in the Griffith classification system). CONCLUSION: MRI obtained with patients standing can show decreases in the lateral recesses and foramina related to the predominance of symptoms while standing, especially in patients aged>40 years with Griffith disc degeneration grade 3 to 6, thus providing additional information in the study of patients who have low back pain when standing in whom the findings on conventional studies are inconclusive or discrepant with their symptoms. Further studies are necessary to help better define the value of upright MRI studies for degenerative lumbar disease.

Biomechanical study of the C5-C8 cervical extraforaminal ligaments.

BACKGROUND: The anatomical distribution of the extraforaminal ligaments in the cervical intervertebral foramina has been well studied. However, detailed descriptions of the biomechanical characteristics of these ligaments are lacking. METHODS: The paravertebral muscles were dissected, and the extraforaminal ligaments and nerve roots were identified. The C5 and C7 or C6 and C8 cervical nerve roots on both sides were randomly selected, and a window was opened on the vertebral lamina to expose the posterior spinal nerve root segments. Five needles were placed on the nerve root and the bone structure around the intervertebral foramen; the distal end of the nerve root was then tied with silk thread, and the weights were connected across the pulley. A weight load was gradually applied to the nerve root (50 g/time, 60 times in total). At the end of the experiment, segments of the extraforaminal ligaments were selectively cut off to compare the changes in nerve root displacement. RESULTS: The displacement of the C5, C6, C7, and C8 nerve roots increases with an increasing traction load, and the rate of change of nerve root displacement in the intervertebral foramen is smaller than that in the nerve root on the outside area (p < 0.05). Extraforaminal ligaments can absorb part of the pulling load of the nerve root; the C5 nerve root has the largest load range. CONCLUSIONS: Cervical extraforaminal ligaments can disperse the tension load on the nerve root and play a role in protecting the nerve root. The protective effect of the C5 nerve root was the strongest, and this may anatomically explain why the C5 nerve roots are less prone to simple avulsion.

[Treatment of cervical spodylotic radiculopathy with posterior intervertebral foraminal discectomy via Delta channel].

OBJECTIVE: To explore the clinical efficacy and safety of posterior intervertebral foraminal discectomy via Delta channel for cervical spondylotic radiculopathy in the early phase. METHODS: From September 2017 to July 2018, 10 patients with cervical spondylotic radiculopathy underwent posterior intervertebral foraminal discectomy via Delta channel. There were 6 males and 4 females, aged from 30 to 62 years old with an average of (41.5±4.3) years old. All of them had unilateral symptoms caused by cervical nerve root compression, including 2 cases of C4,5, 5 cases of C5,6 and 3 cases of C6,7. CT and MRI examination of all the patients did not show ossification of posterior longitudinal ligament or calcification of ligamentum flavum, and no cervical spine instability was present in dynamic radiographs. The clinical outcome was poor after more than 6 weeks of systematic non-surgical treatment. The VAS score, JOA score, NDI score, the cervical spine physiological curvature, and the height and stability of the compressed cervical vertebrae were measured before operation and at the latest follow-up. RESULTS: All patients successfully completed the surgeries without any spinal cord, nerve root or major blood vessel injury. The operation time was 70 to 120 min with an average of 90 min. Intraoperative blood loss ranged from 30 to 90 ml with an average of 40 ml. All the 10 patients were followed up for 6 to 14 months with an average of 9 months. Postoperative nerve root pain got relievd and nerve function was improved in all patients. VAS score decreased from 7.15±2.01 before surgery to 1.59±0.83 at the latest follow-up;JOA score increased from 12.57±1.24 before surgery to 16.42±0.58 at the latest follow-up;NDI score increased from 41.82±4.71 before surgery to 9.59±3.52 at the latest follow-up. All the results above presented significant difference between latest follow-up and preoperative (P< 0.05). The D value of cervical physiological curvature increased from (8.21±0.84) mm before surgery to(10.89±0.96) mm at the latest follow-up, and the difference was also statistically significant (P<0.05). The height of the diseased vertebrae was (5.62± 0.59) mm before surgery and (5.60±0.57) mm at the latest follow-up, with no statistically significant difference(P>0.05). At the latest follow-up, no cervical instability was observed on dynamic radiographs. CONCLUSION: Treatment of cervical spondylotic radiculopathy by posterior intervertebral foraminal discectomy via Delta channel can obtain a satisfactory clinical outcome without affecting the stability of cervical vertebra. The surgery is safe, reliable and worthy of clinical application.

Three-dimensional architecture of the neurovascular and adipose zones of the upper and lower lumbar intervertebral foramina: an epoxy sheet plastination study.

OBJECTIVE: Kambin's triangle and the safe triangle are common posterolateral approaches for lumbar transforaminal endoscopic surgery and epidural injection. To date, no consensus has been reached on the optimal transforaminal approach, in particular its underlying anatomical mechanism. The aim of this study was to investigate the 3D architecture of the neurovascular and adipose zones in the upper and lower lumbar intervertebral foramina (IVFs). METHODS: Using the epoxy sheet plastination technology, 22 cadaveric lumbar spines (12 female and 10 male, age range 46-89 years) were prepared as a series of transverse (11 sets), sagittal (8 sets), and coronal (3 sets) slices with a thickness of 0.25 mm (6 sets) or 2.5 mm (16 sets). The high-resolution images of the slices were scanned and analyzed. The height, area, and volume of 30 IVFs from T12-L1 to L4-5 were estimated and compared. This study was performed in accord with the authors' institutional ethical guidelines and approved by the institutional ethics committees. RESULTS: The findings were as follows. 1) The 3D boundaries of the lumbar IVF and its subdivisions were precisely defined. 2) The 3D configuration of the neurovascular and adipose zones was different between the upper and lower lumbar IVFs; zoning in the upper lumbar IVFs was much more complex than that in the lower lumbar IVFs. 3) In general, the infraneural adipose zone gradually tapered and rotated from the inferoposterolateral aspect to the superoanteromedial aspect. 4) The average height, area, and volume of the IVF gradually increased from the upper to the lower lumbar spine. Within a lumbar IVF, the volumes below and above the inferior border of the dorsal root ganglia were similar. CONCLUSIONS: This study highlights differences of fine 3D architecture of neurovascular and adipose tissues between the upper and lower lumbar IVFs, with related effects on the transforaminal approaches. The findings may contribute to optimization of the surgical approaches to and through the IVF at different lumbar spinal levels and also may help to shorten the learning curve for the transforminal techniques.

Anatomic morphology and clinical significance of intraforaminal ligaments of the cervical spine.

The cause of cervical spondylotic radiculopathy could be related to the intraforaminal ligaments (IFLs) of the cervical spine. The aim of this study is to identify and describe the IFLs and assess their clinical significance. Six intact cervical spine specimens from adult embalmed cadavers were dissected to expose the cervical nerve roots and their surrounding intraforaminal tissues fully. From the C1-C2 to the C7-T1 intervertebral foramina (IVF), the connective structures between each nerve root and its surrounding foraminal wall were examined under a surgical microscope. The morphology, number, and attachment points of the IFLs of each segment were documented, and the length, width, or diameter and thickness of the ligaments were measured with a vernier caliper. IFLs were observed in all 84 IVFs of the cervical spine. According to their locations, they can be divided into two categories: the first is entrance-zone IFLs, which are radially distributed around the nerve root; the second is mid-zone IFLs, which are thin, strip-shaped fibrous tissues intertwined around the nerve roots, the number of ligaments being considerable but difficult to quantify. Ligament structures have been identified in the IVF of the cervical spine. Under physiological conditions, they could be protective in maintaining the position, shape, and function of nerve roots. However, under pathological conditions, the IFLs of the cervical spine could aggravate the symptoms of cervical nerve root radicular pain associated with other types of compression. Clin. Anat. 32:654-660, 2019. © 2019 Wiley Periodicals, Inc.