Foraminal Width Research Articles

Morphometric analysis of cervical neuroforaminal dimensions from C2–T1 using computed tomography of 1,000 patients

BACKGROUNDRace and sex differences are not consistently reported in the literature. Fundamentally, anatomical differences of cervical neuroforaminal dimensions (CNFD) amongst these groups would be important to know. PURPOSETo establish normative radiographic morphometric measurements of CNFD and uncover the influence of patient sex, race, and ethnicity while also considering anthropometric characteristics. STUDY DESIGNRetrospective radiographic morphometric study. PATIENT SAMPLEA total of 1,000 patients between 18 and 35 years of age who were free of spinal pathology. OUTCOME MEASURESForaminal height, axial width, and area of cervical neural foramen. METHODSCervical CTs were reviewed to measure CNFD, defined as follows: foraminal height, axial width, and area. Statistical analyses were performed to assess associations between CNFD, and patient height, weight, sex, race, and ethnicity. RESULTSCNFD measurements followed a bimodal distribution pattern moving caudally from C2–T1. Irrespective of disc level, cervical CNFD were as follows: left and right widths of 6.6±1.5 and 6.6±1.5 mm, heights of 9.4±2.4 and 9.4±3.2 mm, and areas of 60.0±19.5 and 60.6±20.7 mm2. Left and right foraminal width were highest at C2–C3 and lowest at C3–C4. Left and right foraminal height were highest at C7–T1 and C6–C7, respectively and lowest at C3–C4. Left and right foraminal areas were highest at C2–C3 and lowest at C3–C4. Significant differences were observed for all CNFD measurements across disc levels. CNFD did not vary based on laterality. Significant CNFD differences were observed with respect to patient sex, race, and ethnicity. Male height and area were larger compared to females. In contrast, female foraminal width was larger compared to males. The Asian cohort demonstrated the largest foraminal widths. White and Hispanic patients demonstrated the largest foraminal heights and areas. Black patients demonstrated the smallest foraminal widths, heights, and areas. Patient height and weight were only weakly correlated with CNFD measurements across all levels from C2–T1. CONCLUSIONSThis study describes 36,000 normative measurements of 12,000 foramina from C2–T1. CNFD measurements vary based on disc level, but not laterality. Contrasting left- versus right-sided neuroforamina of the same level may aid in determining the presence of unilateral stenosis. Patient sex, race, and ethnicity are associated with CNFD, while patient anthropometric factors are weakly correlated with CNFD.

The Impact of Posterior Intervertebral Osteophytes on Patient-Reported Outcome Measures After L5-S1 Anterior Lumbar Interbody Fusion and Transforaminal Lumbar Interbody Fusion.

Retrospective cohort study. (1) To develop a reliable grading system to assess the severity of posterior intervertebral osteophytes and (2) to investigate the impact of posterior intervertebral osteophytes on clinical outcomes after L5-S1 decompression and fusion through anterior lumbar interbody fusion (ALIF) and minimally-invasive transforaminal lumbar interbody fusion (MIS-TLIF). There is limited evidence regarding the clinical implications of posterior lumbar vertebral body osteophytes for ALIF and MIS-TLIF surgeries and there are no established grading systems that define the severity of these posterior lumbar intervertebral osteophytes. A retrospective analysis of patients undergoing L5-S1 ALIF or MIS-TLIF was performed. Preoperative and postoperative patient-reported outcome measures of the Oswestry Disability Index (ODI) and leg Visual Analog Scale (VAS) at 2-week, 6-week, 12-week, and 6-month follow-up time points were assessed. Minimal clinically important difference (MCID) for ODI of 14.9 and VAS leg of 2.8 were utilized. Osteophyte grade was based on the ratio of osteophyte length to foraminal width. "High-grade" osteophytes were defined as a maximal osteophyte length >50% of the total foraminal width. A total of 70 consecutive patients (32 ALIF and 38 MIS-TLIF) were included in the study. There were no significant differences between the two cohorts in patient-reported outcome measures or achievement of MCID for Leg VAS or ODI preoperatively or at any follow-ups. On multivariate analysis, neither the surgical approach nor the presence of high-grade foraminal osteophytes was associated with leg VAS or ODI scores at any follow-up time point. In addition, neither the surgical approach nor the presence of high-grade foraminal osteophytes was associated with the achievement of MCID for leg VAS or ODI at 6 months. ALIF and MIS-TLIF are both valid options for treating degenerative spine conditions and lumbar radiculopathy, even in the presence of high-grade osteophytes that significantly occupy the intervertebral foramen. 3.

Morphological changes after open lumbar microdiscectomy at 2-year follow-up.

It is known that a possible decrease in disc height (DH) and foraminal size after open lumbar microdiscectomy (OLM) may cause pain in the long term. However, there is still insufficient information about the short- or long-term pathoanatomical and morphological effects of microdiscectomy. For example, the exact temporal course of the change in DH is not well known. The purpose of this study was to examine morphological changes in DH and foramen dimensions after OLM. In patients who underwent OLM for single-level lumbar disc herniation, MRI scans were obtained before surgery, and at an average of two years after surgery. In addition to DH measurements, foraminal area (FA), foraminal height (FH), superior foraminal width (SFW), and inferior foraminal width (IFW), were measured bilaterally. A postoperative increase in DH was observed at all vertebral levels, with an average of 5.5%. The mean right FHs were 15.3mm and 15.7mm before and after surgery, respectively (p= 0.062), while the left FHs were 14.8mm and 15.8mm before and after surgery (p= 0.271). The mean right SFW was 5.4mm before surgery and 5.7mm after surgery, while the mean right IFW ranged from 3.6mm to 3.9mm. The mean left SFW was 4.8mm before surgery and 5.2mm after surgery, while the mean left IFW ranged from 3.5mm to 3.9mm. Before surgery, the FAs were, on average, 77.1mm2 and 75.6mm2 on the right and left sides, respectively. At the 2-year follow-up, the mean FAs were 84.0mm2 and 80.2mm2 on the right and left sides, respectively. Contrary to prevalent belief, in patients who underwent single-level unilateral OLM, we observed that there may be an increase rather than a decrease in DH or foramen size at the 2-year follow-up. Our findings need to be confirmed by studies with larger sample sizes and longer follow-ups.

Normative Measurements of L1-S1 Segmental Angulation, Disk Space Height, and Neuroforaminal Dimensions Using Computed Tomography.

To establish normative anatomic measurements of lumbar segmental angulation (SA) and disk space height (DSH) in relation to neuroforaminal dimensions (NFDs), and to uncover the influence of patient demographic and anthropometric characteristics on SA, DSH, and NFDs. NFDs, SA, and anterior, middle, and posterior DSH were measured using computed tomography of 969 patients. NFDs were defined as sagittal anterior-to-posterior width, foraminal height, and area. Statistical analyses were performed to assess associations among SA, DSH, NFDs, and patient height, weight, body mass index, sex, and ethnicity. SA and DSH measurements increased moving caudally from L1 to S1. Foraminal width decreased moving caudally from L1 to S1. Foraminal height and area demonstrated unimodal distribution patterns with the largest values clustered at L2-L3 on the right side and L3-L4 on the left. Significant differences in SA, DSH, and NFD measurements were observed based on the disk level. Inconsistent, marginal NFD differences were observed based on laterality. Across all disk levels, only weak-to-moderate correlations were observed between SA and DSH in relation to NFDs. Patient height, weight, and body mass index were only weakly associated with SA, DSH, and NFDs. Based on patient sex, significant differences were observed for SA, DSH, and NFD measurements from L1 to S1, with males demonstrating consistently larger values compared with females. Based on patient race and ethnicity, significant differences in SA and NFD measurements were observed from L1 to S1. This study describes 48 450 normative measurements of L1-S1 SA, DSH, and NFDs. These measurements serve as representative models of normal anatomic dimensions necessary for several applications including surgical planning and diagnosis of foraminal stenosis. Normative values of SA and DSH are not moderately or strongly associated with NFDs. SA, DSH, and NFDs are influenced by sex and ethnicity, but are not strongly or moderately influenced by patient anthropometric factors.

Comparison of the Interlaminar and Transforaminal Approaches for Full-endoscopic Discectomy for the Treatment of L4/5 Lumbar Disc Herniation.

This study aims to compare the outcomes of interlaminar and transforaminal approaches for full-endoscopic discectomy (FED) for treating L4/5 lumbar disc herniation (LDH).A retrospective study of patients with L4/5 LDH treated with interlaminar endoscopic lumbar discectomy (IELD, n = 19) or transforaminal endoscopic lumbar discectomy (TELD, n = 105) was conducted. Patient background, radiological findings, and operative data were collected. Oswestry Disability Index (ODI) and European Quality of Life-5 Dimension (EQ-5D) scores were recorded preoperatively and 1 and 2 years postoperatively.Although ODI and EQ-5D scores 1 and 2 years postoperatively improved statistically in the IELD and TELD groups, there were no statistical differences between the groups. IELD was predominantly performed in patients who were taller and heavier. The mean operative times and the frequency of laminectomy for IELD and TELD were 67.2 and 44.6 min and 63.2 and 17.1%, respectively (P < 0.001). The radiological findings showed that the concave configuration of the L4 lamina, interlaminar space width, and foraminal width were statistically different between the groups. There were no complications in either of the groups. Reoperation was required for recurrence in two and five patients in the IELD and TELD groups (P = 0.29), respectively.Operative outcomes were identical between the two groups. Although the operative time was longer in the IELD group, both approaches were safely and effectively performed. Depending on the patient's physique and preoperative radiological findings, the more suitable approach for L4/5 LDH should be chosen.

Clinical and Radiographic Comparison of Oblique Lateral Lumbar Interbody Fusion and Minimally Invasive Transforaminal Lumbar Interbody Fusion in Patients with L4/5 grade-1 Degenerative Spondylolisthesis.

To compare the clinical and radiographic outcomes of oblique lateral lumbar interbody fusion and minimally invasive transforaminal lumbar interbody fusion in patients with grade-1 L4/5 degenerative spondylolisthesis. Based on the inclusion and exclusion criteria, the comparative analysis included consecutive patients with grade-1 degenerative spondylolisthesis who underwent oblique LIF (OLIF, n= 36) or minimally invasive transforaminal LIF (MI-TLIF, n=45) at the Department of Spine Surgery, Beijing Jishuitan Hospital from January 2016 to August 2017. Patient satisfaction Japanese Orthopaedic Association score, visual analog scale (VAS) scores for back and leg pain, Oswestry disability index (ODI), radiographic outcomes including anterior/posterior disc heights (ADH/PDH), foraminal height (FH), foraminal width (FW), cage subsidence, cage retropulsion, and fusion rate were assessed during a 2-year follow-up. Continuous data are presented as mean ± standard deviation and were compared between groups using the independent sample t-test. Categorical data are presented as n (%) and were compared between groups using the Pearson chi-squared test or Fisher's exact test. Repetitive measurement and analysis of variance was employed in the analysis of ODI, back pain VAS score, and leg pain VAS score. Statistical significance was defined as p< 0.05. The OLIF and MI-TLIF groups comprised 36 patients (age, 52.1 ± 7.2 years; 27 women) and 45 patients (age, 48.4 ± 14.4 years; 24 women), respectively. Satisfaction rates at 2 years post procedure exceeded 90% in both groups. The OLIF group had less intraoperative blood loss (140 ± 36 vs 233 ± 62 mL), lower back pain VAS score (2.42 ± 0.81 vs 3.38 ± 0.47), and ODI score (20.47 ± 2.53 vs 27.31 ± 3.71) at 3 months follow-up (with trends toward lower values at 2 years follow-up), but higher leg pain VAS scores at all postoperative time points than the MI-TLIF group (all p < 0.001). ADH, PDH, FD, and FW improved in both groups post-surgery. At the 2 year follow-up, the OLIF group had a higher rate of Bridwell grade-I fusion (100% vs 88.9%, p=0.046) and lower incidences of cage subsidence (8.33% vs 46.67%, p < 0.001) and retropulsion (0% vs 6.67%, p=0.046) than the MI-TLIF group. In patients with grade-I spondylolisthesis, OLIF was associated with lower blood loss and greater improvements in VAS for back pain and ODI and radiologic outcomes than MI-TLIF. The OLIF is more suitable for these patients with low back pain as the main symptoms are accompanied by mild or no leg symptoms before operation.

Correlation of Foraminal Parameters with Patient-Reported Outcomes in Patient with Degenerative Lumbar Foraminal Stenosis.

The relationship between quantitative anatomic parameters in MRI and patient-reported outcomes (PROs) before and after surgery in degenerative lumbar foraminal stenosis remains unknown. We included 58 patients who underwent transforaminal lumbar interbody fusion (TLIF) for single-level degenerative disc disease with foraminal stenosis between February 2013 and June 2020. PROs were evaluated using the visual analog scale (VAS) for back and leg pain, Oswestry Disability Index (ODI), and EuroQol-5D (EQ-5D). The foraminal parameters assessed using preoperative MRI included foraminal height, posterior intervertebral disc height, superior and inferior foraminal width, and foraminal area. The correlation between foraminal parameters and PROs before operation, at 1 year follow-up, and change from baseline were assessed. The associations between the aforementioned parameters were examined using linear regression analysis. The analysis revealed that among these parameters, superior foraminal width was found to be significantly correlated with ODI and EQ-5D at the 1 year follow-up and with change in ODI and EQ-5D from baseline. The associations remained significant after adjustment for confounding factors including age, sex, body mass index, and duration of hospital stay. The results indicated that in degenerative lumbar foraminal stenosis, decreased superior foraminal width was associated with better improvement in disability and quality of life after TLIF.

Comparative Study of the Differences in Radiologic Results for Percutaneous Endoscopic Lumbar Foraminotomy and Microscopic or Micro-endoscopic Lumbar Foraminotomy

Objective: Lumbar foraminal stenosis is a common pathology that causes back pain and radiculopathy. Percutaneous endoscopic lumbar foraminotomy (PELF) is a minimally invasive surgical procedure reported to be effective in the treatment of foraminal stenosis; however, no studies have been conducted that compare the on radiographic results of PELF and conventional techniques for the treatment of foraminal stenosis, such as microscopic foraminotomy and micro-endoscopic foraminotomy. This study aimed to report postoperative changes in the lumbar foraminal parameters on computed tomography (CT) after PELF and to compare the radiological efficacy of the PELF technique with that of the conventional techniques.Methods: Radiographic evaluation of the neuroforamen was based on CT scans taken preoperatively and 3 months postoperatively in the PELF and conventional groups. The Japanese Orthopaedic Association (JOA) score for back pain, visual analog scale (VAS), and JOA back pain evaluation questionnaire (JOABPEQ) were evaluated preoperatively and at 3 months postoperatively in the PELF group.Results: The PELF and conventional groups comprised 21 and 17 patients, respectively. In the PELF group, the JOA score, VAS of back pain, and JOABPEQ of low back pain showed significant improvement; however, VAS of leg pain and leg numbness and the other components of JOABPEQ showed no significant differences. There were significant increases in the foraminal area, superior foraminal width (SFW), and middle foraminal width (MFW). Additional radiological evaluation for patients who underwent microscopic or micro-endoscopic lumbar foraminotomy was almost equivalent.Conclusion: Percutaneous endoscopic lumbar foraminotomy is a minimally invasive technique that is as effective as conventional techniques for the treatment of foraminal stenosis.

Restoring Segmental Spinal Alignment in Mini-Open Lateral Spinal Deformity Surgery-Determiners of Radiographic Outcome.

Both under- and overcorrection are risk factors for junctional failure after deformity correction. This study investigates which factors determine the segmental radiographic outcome in mini-open lateral deformity surgery. A single-center operative database was searched for patients undergoing multilevel mini-open lateral corrective surgery of degenerative spinal deformities. Preoperative and postoperative whole spine x-rays and computed tomography scans were compared for change in global and segmental alignment parameters. Linear regression analyses were performed to study the impact of surgical level, preoperative segmental sagittal Cobb angle, presence of bridging osteophytes, disc height, ankylosis of facet joints, and implantation site of the interbody device on postoperative increase in segmental lordosis, foraminal height, and foraminal width. A total of 49 patients were identified with a mean age of 68.7 years. At a mean, 4.2 segments were fused using a lateral approach, while the posterior stage comprised either minimally invasive surgery or open instrumentation. Upper instrumented vertebra was L2 (range T4-L3), and lower instrumented vertebra was L5 (range L4-pelvis) in most cases. Mean radiographic values pre- and postoperatively were as follows: C7 sagittal vertical axis +79.6 mm, +60 mm; lumbar lordosis 32.9°, 41.6°; pelvic tilt 21.1°, 21.8°; global coronal Cobb 16.3°, 10.8°; increase in segmental sagittal Cobb angle was significantly and inversely correlated with preoperative sagittal Cobb and positively correlated with preoperative coronal Cobb angle. No other variable showed significant correlations. Preoperative foraminal width and height showed significant and inverse correlation with change in postoperative foraminal width and height. Segmental sagittal correction is significantly influenced by preoperative loss of lordosis and coronal Cobb angle. Neither presence of osteophytes nor ankylosed facet joints, disc height, or implantation site of the interbody device had an influence on sagittal alignment goals. Only preoperative foraminal dimensions impact inversely the degree of foraminal decompression; no other factor investigated showed significant impact. Only preoperative lordosis and coronal Cobb angle influence sagittal correction.

May the midline lumbar interbody fusion (MIDLIF) prevent the early radiographic adjacent segment degeneration? A minimum 3-year follow-up comparative study of MIDLIF in L4/5 with cortical bone trajectory screw versus traditional pedicle screw fixation

Study designRetrospective cohort study.ObjectiveTo compare the early radiographic adjacent segment degeneration (R-ASD) and regional lumbar sagittal alignment after midline lumbar interbody fusion (MIDLIF) with cortical bone trajectory (CBT) screw fixation (CBT-MIDLIF) and posterior lumbar interbody fusion (PLIF) with the traditional pedicle screw fixation (PS-PLIF) during long-term follow-up.MethodsAll patients who underwent CBT-MIDLIF or PS-PLIF were identified by a retrospective consecutive case review. Radiographic parameters in cephalad adjacent segment (L3/4), including intervertebral space height (ISH), foraminal height (FH), foraminal width (FW), range of motion were assessed. Lumbar lordosis (LL), sacral slope (SS), L4–L5 Cobb angle, Cobb angle of the intervertebral space at L4–L5, and height of the anterior and posterior edges of the intervertebral space at L4–L5, were measured and compared on preoperative, postoperative, and 3-year follow-up radiographic evaluation.ResultsSeventy-four patients underwent CBT-MIDLIF (CBT-MIDLIF group) and 114 patients underwent conventional PS-PLIF (PS-PLIF group). ISH, FH and FW were significantly smaller at 6-month follow-up than before operation with PS-PLIF (p < 0.001) but showed no significant changes with CBT-MIDLIF (p > 0.05). At the last follow-up, the changes in cephalad R-ASD parameters were more remarkable after PS-PLIF than after CBT-MIDLIF (p < 0.01). LL and SS were significant larger at the last follow-up than before operation in both groups (p < 0.001). Regarding long-term outcomes, the symptoms caused by degenerative spinal disorders significantly improved in both groups (p < 0.01).ConclusionCBT-MIDLIF had less radiographic degeneration in the adjacent segment than PS-PLIF at 3-year follow-up. The lumbar sagittal alignment could be improved significantly and the surgical outcomes were satisfactory after either CBT-MIDLIF or PS-PLIF.

Tomodensitometric bone anatomy of the intervertebral foramen of the lower cervical spine: measurements and comparison of foraminal volume in healthy individuals and patients suffering from cervicobrachial neuralgia due to foraminal stenosis.

Degenerative foraminal stenosis of the cervical spine can lead to cervicobrachial neuralgias. Computed tomography (CT)-scan assists in the diagnosis and evaluation of foraminal stenosis. The main objective of this study is to determine the bony dimensions of the cervical intervertebral foramen and to identify which foraminal measurements are most affected by degenerative disorders of the cervical spine. These data could be applied to the surgical treatment of this pathology, helping surgeons to focus on specific areas during decompression procedures. A descriptive study was conducted between two groups: an asymptomatic one (young people with no evidence of degenerative cervical spine disorders) and a symptomatic one (experiencing cervicobrachial neuralgia due to degenerative foraminal stenosis). Using CT scans, we determined a method allowing measurements of the following foraminal dimensions: foraminal height (FH), foraminal length (FL), foraminal width in its lateral part ((UWPP, MWPP and IWPP (respectively Upper, Medial and Inferior Width of Pedicle Part)) and medial part (UWMP, MWMP and IWMP (respectively Upper, Medial and Inferior Width of Medial Part)), and disk height (DH). Foraminal volume (FV) was calculated considering the above data. Mean volumes were measured in the asymptomatic group and compared to the values obtained in the symptomatic group. Both groups were made up of 10 patients, and a total of 50 intervertebral discs (100 intervertebral foramina) were analyzed in each group. Comparison of C4C5, C5C6 and C6C7 levels between both groups showed several significant decreases in foraminal dimensions (p < 0.05) as well as in foraminal volume (p < 0.001) in the symptomatic group. The most affected dimensions were UWPP, MWPP, UWMP, MWMP and FV. The most stenotic foraminal areas were the top of the uncus and the posterior edge of the lower plate of the overlying vertebra. Using a new protocol for measuring foraminal volume, the present study refines the current knowledge of the normal and pathological anatomy of the lower cervical spine and allows us to understand the foraminal sites most affected by degenerative stenosis. Those findings can be applied to foraminal stenosis surgeries. According to our results, decompression of the foramen in regard of both uncus osteophytic spurs and inferior plate of the overlying vertebra might be an important step for spinal nerves release.

Contralateral radiculopathy after unilateral transforaminal lumbar interbody fusion: causes and prevention.

BackgroundUnilateral transforminal lumbar interbody fusion (TLIF) with a single cage can provide circumferential fusion and biomechanical stability. However, the causes and prevention of contralateral radiculopathy following unilateral TLIF remain unclear.MethodsIn total, 190 patients who underwent unilateral TLIF from January 2017 to January 2019 were retrospectively reviewed. Radiological parameters including lumbar lordosis, segmental angle, anterior disc height, posterior disc height (PDH), foraminal height (FH), foraminal width, and foraminal area (FA) were measured preoperatively and postoperatively. Preoperative and postoperative visual analog scale scores were also recorded.ResultsThe incidence of contralateral radiculopathy after unilateral TLIF was 5.3% (10/190). The most common cause was contralateral foraminal stenosis. Unilateral TLIF could increase the lumbar lordosis, segmental angle, and anterior disc height but decrease the PDH, FA, and FH in patients with symptomatic contralateral radiculopathy. The intervertebral cage should be placed to cover the epiphyseal ring and cortical compact bone of the midline, and the disc height can be increased to enlarge the contralateral foramen.ConclusionThe most common cause of contralateral radiculopathy is contralateral foraminal stenosis. Careful preoperative planning is necessary to achieve satisfactory outcomes. Improper unilateral TLIF will decrease the PDH, FA, and FH, resulting in contralateral radiculopathy.

Analysis of risk factors for C5 nerve root paralysis after posterior cervical decompression

BackgroundC5 nerve root paralysis is a nonnegligible complication after posterior cervical spine surgery (PCSS). The cause of its occurrence remains controversial. The purpose of this study was to analyse the incidence of and risk factors for C5 nerve root paralysis after posterior cervical decompression.MethodsWe retrospectively analysed the clinical data of 640 patients who underwent PCSS in the Department of Orthopaedics, Affiliated Hospital of Qingdao University from September 2013 to September 2019. According to the status of C5 nerve root paralysis after surgery, all patients were divided into paralysis and normal groups. Univariate and multivariate analyses were used to determine the independent risk factors for C5 nerve root paralysis. A receiver operating characteristic (ROC) curve was used to demonstrate the discrimination of all independent risk factors.ResultsMultivariate logistic regression analysis revealed that male sex, preoperative cervical spine curvature, posterior longitudinal ligament ossification, and preoperative C4/5 spinal cord hyperintensity were independent risk factors for paralysis, whereas the width of the intervertebral foramina was an independent protective factor for paralysis. The area under the curve (AUC) values of the T2 signal change at C4-C5, sex, cervical foramina width, curvature and posterior longitudinal ligament ossification were 0.706, 0.633, 0.617, 0.637, and 0.569, respectively.ConclusionsMale patients with C4-C5 intervertebral foramina stenosis, preoperative C4-C5 spinal cord T2 high signal, combined with OPLL, and higher preoperative cervical spine curvature are more likely to develop C5 nerve root paralysis after surgery. Among the above five risk factors, T2 hyperintensity change in C4-C5 exhibits the highest correlation with C5 paralysis and strong diagnostic power. It seems necessary to inform patients who have had cervical spine T2 hyperintensity before surgery of C5 nerve root paralysis after surgery, especially those with altered spinal cord T2 signals in the C4-C5 segment.

Foraminal Stenosis as a Cause of Postdiscectomy Syndrome.

To reveal the relation between postdiscectomy syndrome and foraminal stenosis due to height loss of disc level in patients operated for one-sided L5-S1 disc herniation. 100 operated patients due to L5-S1 one-sided disc herniation were included. Mean age was 46.60 years (±10.52 years). Foraminal height, width, and intervertebral disc height were measured via CT. The diameters were compared preoperatively and postoperatively. The relation between the measurements and clinic findings was investigated. Six months after discectomy, for the operated side, the mean foraminal height decreased from 16.78 ± 1.75 mm to 14.43 ± 1.62 mm (p 0.05) and the mean foraminal width decreased from 6.30 ± 1.43 mm to 5.34 ± 1.56 mm (p 0.05). According to the correlation test, for the operated side, a statistically significant relationship was observed between the decrease in foramen height and leg pain visual analog scale (VAS) score. Moreover, a statistically significant relationship was observed between the decrease in the posterior side height of the disc level and the leg pain VAS score. Overall, after microdiscectomy, as the height of the foramen decreased, leg pain also increased. Moreover, the decrease in the posterior side height of the disc level was associated with an increase in leg pain. Therefore, over time, the collapse of the disc distance decreases the foramen height, which causes leg pain. After microdiscectomy, in patients whose leg pain was relieved at first but started again after a time, the foramen and disc level diameters should be checked.

Changes of MRI in inter-spinal distraction fusion for lumbar degenerative disease: A retrospective analysis covering 3 years

ObjectiveTo assess the preoperative and postoperative changes in MRI image and the short-term efficacy of the ISDF with BacFuse covering 3 years. Methods32 patients who underwent ISDF were involved in this retrospective study. The symptoms assessment including VAS, ODI, and SF-12 were evaluated preoperative and postoperative at 1 year and 3 years. The X-ray was used to measure posterior disk height (PDH), foramina height (FH), foramina width (FW), and MRI was taken to assess the cross-sectional area of dura sac (CSADS), cross-sectional area of canal (CSAC), herniated disc area, ligamentum flavum area. The preoperative ratio of herniated disc area and ligamentum flavum area to CSAC were compared with post-operative ratio. The modified Pfirrmann grade system was used to assess the surgical lumbar disc. ResultsThe symptom indexes were significantly improved after surgery. PDH and FH increased significantly (P < 0.05) after surgery compared with that before surgery, but there was no statistical difference in FW (P > 0.05). CSADS and CSAC increased obviously (P < 0.05), while the area of herniated disc and ligamentum flavum decreased significantly (P < 0.05). The ratio changes showed a significant difference between last follow-up and pre-operation (P < 0.05), but there was no statistical significance in grade changes of surgical disc. ConclusionISDF with BacFuse could relieve clinical symptoms and expanse the spinal canal area in MRI. During 3-year observation, it could provide continuous traction and maintain the area of spinal canal, so as to partially retract the herniated disc and make it possible to repair the disc.

Dimensional Changes of Lumbar Intervertebral Foramen in Direct Anterior Approach-Specific Hyperextension Supine Position.

ObjectiveTo investigate the changes in the lumbar intervertebral foramen (LIVF) dimensions from neutral supine to direct anterior approach (DAA)‐specific hyperextension supine position through a standardized three‐dimensional (3D) reconstruction computerized tomography (CT) method.MethodsA total of 35 healthy volunteers (18 men and 17 women) were included in this retrospective study. The mean age of enrolled subjects was 28.9 ± 5.0 years. In September 2018, all the individuals underwent a 3D CT scan of the lumbar spine in neutral and 30° hyperextension supine positions, which mimicked the patient’s position in DAA total hip arthroplasty (THA). The dimensions of the LIVF, including foraminal area, height, and width, were measured on 3D reconstructed CT models at all lumbar foraminal levels. Foraminal area was defined as the area bounded by the adjacent superior and inferior vertebral pedicles, the posterosuperior boundary of the inferior vertebral body, the surface of the intervertebral disc posteriorly, the posteroinferior boundary of the superior vertebral body, and the surface of the ligamentum flavum anteriorly. Foraminal height was defined as the longest distance between the border of the superior and the inferior pedicle. Foraminal width was defined as the shortest distance between the posteroinferior edge of the superior vertebrae and the opposing boundary. Subgroup analysis and multiple linear regression were used to evaluate the relationship between percentage changes of the LIVF dimensions and side, sex, and age.ResultsThe LIVF dimensions varied significantly between the two positions at all levels (P < 0.05). From neutral to hyperextension supine position, the foraminal area reduced by 20.1% at lumbar 1–2 (L1–2), 22.6% at L2–3, 19.9% at L3–4, 18.1% at L4–5, and 12.0% at lumbar 5–sacral 1 (L5–S1) level, respectively; the foraminal height reduced by 9.5% at L1–2, 10.5% at L2–3, 9.5% at L3–4, 9.6% at L4–5, and 6.1% at L5–S1 level, respectively; the foraminal width reduced by 12.8% at L1–2, 14.5% at L2–3, 13.0% at L3–4, 10.4% at L4–5, and 8.4% at L5–S1 level, respectively. The changes in LIVF dimensions were biggest at L2–3 level and smallest at L5–S1 level. Subgroup analysis showed that there were no significant differences in the percentage changes of LIVF dimensions between the sexes and sides (P > 0.05). Multiple linear analysis showed that the percentage changes of LIVF dimensions were not related to side, sex, and age (P > 0.05).ConclusionThe dimensions of the LIVF showed significant decrease at all levels in the DAA‐specific hyperextension supine position compared with the neutral supine position, and the percentage changes of LIVF dimensions were not influenced by side, sex, and age.

Morphologic Changes of Intervertebral Foramen After Minimally Invasive Transforaminal Lumbar Interbody Fusion: A Radiographic and Clinical Study

We aimed to investigate the morphologic changes in the intervertebral foramen after minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF), and analyze the necessity of routinely performing contralateral intervertebral foraminal decompression in degenerative lumbar spondylolisthesis cases with bilateral symptoms. 72 single-level degenerative lumbar spndylolisthesis patients with bilateral symptoms were included, all of whom underwent unilateral approach MIS-TLIF. Preoperative and postoperative foraminal height (FH), foraminal width (FW), disc height (DH), distance from existing nerve root to upper edge of lower pedicle (RTP), and contralateral side spinal canal area (CSCA) were measured at surgical and contralateral side. Clinical outcomes were evaluated using the visual analog scale, Oswestry Disability Index, and Japanese Orthopaedic Association score. The preoperative values are comparable between operative and contralateral sides (P > .05). The postoperative values for FH on operative and contralateral sides were 16.23±2.48 mm and 16.10±2.42 mm, for FW were 11.36±2.58 mm and 11.31±2.71 mm, for IH were 8.18±1.58 mm and 8.42±1.54 mm, for RTP were 8.58±1.26 mm and 9.14±1.77 mm, and the CSCA of the spinal canal on the contralateral side were 211.59±48.12 mm², respectively. The difference between these was also not statistically significant (P > .05). The values increased significantly on the surgical and contralateral side (P < .05). The visual analog scale for low-back and leg pain, Japanese Orthopaedic Association, and Oswestry Disability Index improved significantly at 2-year follow-up. Unilateral MIS-TLIF can effectively improve contralateral FH, DH, FW, RTP, and CSCA. It is not necessary to routinely perform contralateral intervertebral foramen decompression in degenerative lumbar spondylolisthesis with bilateral symptoms when symptoms are mild on one side.

Minimally invasive surgery for low-grade spondylolisthesis: percutaneous endoscopic or oblique lumbar interbody fusion.

Aim: To compare the clinical and radiographic outcomes of percutaneous endoscopic-assisted lumbar interbody fusion (PELIF) versus oblique lumbar interbody fusion (OLIF) for the treatment of symptomatic low-grade lumbar spondylolisthesis. Material & methods: The clinical and radiographic records of 48 patients underwent single-level minimally invasive lumbar fusion with a PELIF (n=16) or OLIF (n=32) were reviewed. Results: The clinical and radiographic outcomes were similar in both groups. PELIF procedure exhibited superior capability of the enlargement of foraminal width, but inferior capability of the restoration of foraminal height than OLIF procedure. Conclusion: PELIF minimizes the iatrogenic damages and perioperative risks to a great extent, and seems to be a promising option for the treatment of symptomatic low-grade lumbar spondylolisthesis.

Standalone oblique lateral interbody fusion vs. combined with percutaneous pedicle screw in spondylolisthesis

BackgroundTo compare standalone oblique lateral interbody fusion (OLIF) vs. OLIF combined with posterior bilateral percutaneous pedicle screw fixation (OLIF combined) for the treatment of lumbar spondylolisthesis.MethodsThis was a retrospective study of patients who underwent standalone OLIF or combined OLIF between 07/2014 and 08/2017 at two hospitals in China. Direct decompressions were not performed. Visual analog scale (VAS), Oswestry Disability Index (ODI), satisfaction rate, anterior/posterior disc heights (DH), foraminal height (FH), foraminal width (FW), cage subsidence, cage retropulsion, fusion rate, and complications were analyzed. All imaging examinations were read independently by two physicians and the mean measurements were used for analysis.ResultsA total of 73 patients were included: 32 with standalone OLIF and 41 with combined OLIF. The total complication rate was 25.0% with standalone OLIF and 26.8% with combined OLIF. There were no differences in VAS and ODI scores by 2 years of follow-up, but the scores were better with standalone OLIF at 1 week and 3 months (P < 0.05). PDH and FW was smaller in the combined OLIF group compared with the standalone OLIF group before and after surgery (all P < 0.05). There were significant differences in FH before surgery and at 1 week and 3 months between the two groups (all P < 0.05), but the difference disappeared by 2 years (P = 0.111). Cage subsidence occurred in 7.3% (3/41) and 7.3% (3/41) of the patients at 3 and 24 months, respectively, in the combined OLIF group, compared with 6.3% (2/32) and 15.6% (5/32), respectively, in the standalone OLIF group at the same time points (P = 0.287). There was no cage retropulsion in both groups at 2 years. The fusion rate was 85.4%(35/41) in the combined OLIF group and 84.4% (27/32) in the standalone OLIF group at 3 months(P = 0.669). At 24 months, the fusion rate was 100.0% in the combined OLIF group and 93.8% (30/32) in the standalone OLIF group (P = 0.066).ConclusionStandalone OLIF may achieve equivalent clinical and radiological outcomes than OLIF combined with fixation for spondylolisthesis. The rate of complications was similar between the two groups. Patients who are osteoporotic might be better undergoing combined rather than standalone OLIF. The possibilty of proof lies within a future prospective study, preferably an RCT.

Three-dimensional morphological analysis of cervical foraminal stenosis using dynamic flexion-extension computed tomography images

BackgroundMorphological features of foraminal stenosis in cervical spondylotic radiculopathy and the adequate extent of facet resection in posterior cervical foraminotomy remain uncertain. Herein, we evaluated quantitatively foraminal widths in cervical spondylotic radiculopathy on dynamic flexion-extension computed tomography using a novel three-dimensional analysis method and determined the extent of facet resection in posterior cervical foraminotomy. MethodsSeventeen patients undergoing posterior cervical foraminotomy for cervical spondylotic radiculopathy were evaluated. A neuroforamen three-dimensional model was built from preoperative images of flexion-extension computed tomography myelography, and an ordinary cervical spine coordinate system and an original neuroforaminal coordinate system, were established. In the neuroforaminal coordinate system, minimum areas perpendicular to the long axis by the slices from inlet to outlet of neuroforamen and narrowest foraminal width in a slice of minimum area were measured. The location of the narrowest region from inlet of the foramen was calculated. Ratios of minimum and sufficient facet resection were obtained from the location of the narrowest region in the neuroforaminal coordinate system. ResultsThe narrowest foraminal widths (flexion/extension) in the cervical spine coordinate system and the neuroforaminal coordinate system were 2.9/2.3 and 2.6/1.9 mm, respectively. The mean values of the location of the narrowest region (flexion/extension) were 0.27/0.22 and 0.50/0.45 mm, respectively, and the narrowest region in the neuroforaminal coordinate system was located on the outer side than in the cervical spine coordinate system (p < 0.001). The ratios of minimum and sufficient facet resection were 23 ± 8% and 32 ± 9%, respectively. ConclusionsThe narrowest regions both in flexion and extension are located at the middle of the foramen based on the neuroforaminal coordinate system. Ordinary evaluation of axial computed tomography images likely underestimates the extent of facet resection, whereas certain extent of facet resection does not exceed 50% in cases with single-level cervical spondylotic radiculopathy. Study designA retrospective case control study.