Magnetic resonance anatomic study of iliocava junction and left iliac vein positions related to L5-S1 disc

STUDY DESIGN: An in vivo anatomic study analyzing the venous anatomy in the lumbosacral area was performed. OBJECTIVES: To obtain in vivo data concerning iliocava junction and left common iliac vein positions at L5-S1. SUMMARY OF BACKGROUND DATA: The left common iliac vein and the iliocava junction are at risk during L5-S1 anterior lumbar interbody fusion. Anatomic studies have demonstrated great interindividual variability in this vascular anatomy. METHODS: Magnetic resonance angiography was used to study 134 patients. Image processing was carried out with maximum intensity projection algorithm and the maximum intensity projection and addition algorithm. Iliocava junction position was measured in the maximum intensity projection and addition image. Four groups of junction position were established: very high, high, low, and very low. The left common iliac vein position was measured in axial magnetic resonance images, and three groups were established: lateral, intermediate, and medial. To describe the operative window delimited by the venous structures at L5-S1, the study population was classified into 12 configurations by combining junction position and vein position values. RESULTS: Very high lateral included 3.76% of the patients, high lateral 48.12%, high intermediate 10.53%, high medial 0.75%, low lateral 15.04%, low intermediate 4.51%, low medial 6.77%, very low lateral 0.75%, very low intermediate 2.26%, and very low medial 7.52%. Medial vein position was significantly more frequent in men. CONCLUSIONS: In 18.05% of the study population, the venous structures overlapped the center of the L5-S1 disc, reducing the operative window.     

Inclusion of L5–S1 in oblique lumbar interbody fusion–techniques and early complications–a single center experience

Background contextThe oblique prepsoas retroperitoneal approach to the lumbar spine for interbody fusion or oblique lumbar interbody fusion (OLIF) provides safe access to nearly all lumbar levels. A wide interval between the psoas and aorta allows for a safe and straightforward left-sided oblique approach to the discs above L5. Inclusion of L5–S1 in this approach, however, requires modifications in the technique to navigate the complex and variable vascular anatomy distal to the bifurcation of the great vessels. While different oblique approaches to L5–S1 have been described in the literature, to our knowledge, no previous study has provided guidance for the choice of technique.PurposeOur objectives were to evaluate our early experience with the safety of including L5–S1 in OLIF using 3 different approach techniques, as well as to compare early complications between OLIF with and without L5–S1 inclusion.Study designRetrospective cohort study.Patient sampleOf the 87 patients who underwent lumbar interbody fusion at 167 spinal levels via an OLIF approach, 19 included L5–S1 (group A) and 68 did not (group B).Outcome measuresDemographics, levels fused, indications, operative time (ORT), estimated blood loss (EBL), vascular ligation, intraoperative blood transfusion, length of stay (LOS), discharge to rehabilitation facility, and complications (intraoperative, early ≤90 days, and delayed >90 days) were retrospectively assessed and compared between the groups.MethodsA retrospective chart and imaging review of all consecutive patients who underwent OLIF at a single institution was performed. Indications for OLIF included symptomatic lumbar degenerative stenosis, deformity, and spondylolisthesis. The L5–S1 level, when included, was approached via one of the following 3 techniques: (1) a left-sided intrabifurcation approach; (2) left-sided prepsoas approach; and (3) right-sided prepsoas approach. Vascular anatomic variations at the lumbosacral junction were evaluated using the preoperative magnetic resonance imaging (MRI), and a “facet line” was proposed to assess this relationship. A minimum of 6 months of follow-up data were assessed for approach-related morbidities.ResultsDemographics and operative indications were similar between the groups. The mean follow-up was 10.8 (6–36) months. ORT was significantly longer in group A than in group B (322 vs. 256.3 min, respectively; p=.001); however, no difference in ORT between the two groups was found in the subanalyses for 2- and 3-level surgeries. Differences in EBL (260 vs. 207.91 cc, p=.251) and LOS (2.76 vs. 2.48 days, p=.491) did not reach statistical significance. Ligation of the iliolumbar vein, segmental veins, median sacral vessels, or any vascular structure, as needed for adequate exposure, was required in 13 (68.4%) patients from group A and 4 (5.9%) from group B (p<.00001). Two patients suffered minor vascular injuries (1 in each group); however, no major vascular injuries were seen. Complications were not significantly different between groups A and B, or between the three approaches to L5–S1, and trended lower in the latter part of the series as the learning curve progressed.ConclusionsInclusion of L5–S1 in OLIF is safe and feasible through three different approaches but likely involves greater operative complexity. In our early experience, inclusion of L5–S1 showed no increase in early complications. This is the first series that reports the use of 3 different oblique approaches to L5–S1. The proposed “facet line” in the preoperative MRI may guide the choice of approach.     

Adjacent fracture-dislocations of the lumbosacral spine: case report

OBJECTIVE AND IMPORTANCE: Traumatic fracture-dislocations of the lumbosacral junction are rare, with all previously reported cases involving fracture-dislocations at a single level. No cases of multiple fracture-dislocations of contiguous spinal segments in the lumbosacral spine have been reported. A case of traumatic adjacent fracture-dislocations of the fifth lumbar segment is presented. CLINICAL PRESENTATION: An 18-year-old male patient sustained open lumbar spinal trauma after a motor vehicle accident. A neurological examination revealed an L4 level. Radiographic evaluation of the spine revealed a three-column injury at L5 with spondyloptosis of the L5 vertebral body. Aorto-ilio-femoral angiography revealed no evidence of vascular injury. INTERVENTION: The patient was treated with a combined anterior and posterior approach in a two-stage operation. Six months postoperatively, he was neurologically unchanged; however, he was able to walk with the aid of a cane. Plain films revealed normal alignment of the lumbosacral spine. CONCLUSION: The management of traumatic lumbosacral fracture-dislocations requires careful consideration of retroperitoneal structures and possible exploration of the iliac vessels in addition to spinal reconstruction.     

S1 screw bending moment with posterior spinal instrumentation across the lumbosacral junction after unilateral iliac crest harvest

STUDY DESIGN: A biomechanical study comparing fixation across the lumbosacral junction. OBJECTIVES: To determine which long posterior construct across the lumbosacral junction produces the least bending moment on the S1 screw when only one ilium is available for fixation. SUMMARY OF BACKGROUND DATA: Recent in vitro studies have demonstrated the benefit of anterior support and fixation into the ilium when instrumenting a long posterior construct across the lumbosacral junction. METHODS: Four L2-sacrum constructs were tested on six synthetic models of the lumbar spine and pelvis simulating that the right ilium had been harvested. Construct 1: L2-S1 bilateral screws. Construct 2: L2-S1 + left iliac bolt. Construct 3: L2-S1 + left iliac bolt + right S2 screw. Construct 4: L2-S1 + bilateral S2 screws. The four constructs were then retested with an anterior L5-S1 strut. A flexion-extension moment was applied across each construct, and the moment at the left and right S1 pedicle screw was measured with internal strain gauges. RESULTS: Iliac bolt fixation was found to significantly decrease the flexion-extension moment on the ipsilateral S1 screw by 70% and the contralateral screw by 26%. An anterior L5-S1 strut significantly decreased the S1 screw flexion-extension moment by 33%. Anterior support at L5-S1 provided no statistical decrease in the flexion-extension moment when bilateral posterior fixation beyond S1 was present with either a unilateral iliac bolt and contralateral S2 screw, or bilateral S2 screws. CONCLUSIONS: There is a significant decrease in the flexion-extension moment on the S1 screw when extending long posterior constructs to either the ilium or S2 sacral screw. There is no biomechanical advantage of the iliac bolt over the S2 screw in decreasing the moment on the S1 screw in flexion and extension. Adding anterior support to long posterior constructs significantly decreases the moment on the S1 screw. Adding distal posterior fixation to either the ilium or S2 decreases the moment on S1 screws more than adding anterior support. Further, adding anterior support when bilateral distal fixation past S1 is already present does not significantly decrease the moment on the S1 screws in flexion and extension.     

Traumatic lumbosacral fracture dislocation: a case report and review of the literature

Lumbosacral dislocation is uncommon. We report a case of traumatic lumbosacral dislocation which occurred in a 33-year-old pedestrian traffic accident victim. The posterior impact produced lumbar injury with diffuse pain exacerbated at the lumbosacral junction. Ecchymotic diffusion involving the entire lumbar region fluctuated due to the presence of a subcutaneous hematoma. The neurological examination revealed incomplete L5 paraplegia. Standard x-rays revealed L5-S1 spondylolisthesis and fracture of the L5 spinous process as well as fractures of the L3, L4, and L5 transverse processes. Computed tomography disclosed biarticular L5-S1 fracture dislocation and a voluminous herniation of the L5-S1 disc. Emergency surgery was performed and revealed subaponeurotic detachment from T4 to S1 and bald iliac pyramids. After L5 laminectomy and extraction of the voluminous herniation of the L5-S1 disc, a short L5-S1 posteriolateral fusion was achieved using pedicular screws and two rods on either side as well as a posterolateral iliac autograft. The clinical course was satisfactory with nearly complete neurological recovery (persistent levator ani paresis). This clinical case and a review of the literature illustrate the pathogenic, clinical, radiological and therapeutic aspects of lumbosacral fracture dislocation.     

Radiographic analysis of lumbar motion in relation to lumbosacral stability. Investigation of moderate and maximum motion

STUDY DESIGN: This in vivo study was performed to examine active lumbar motion without any support. OBJECTIVES: To establish the behavior of segmental flexibility according to the degree of whole lumbar motion and to clarify the correlation between bony characteristics of the lumbosacral junction and stability in the segment. SUMMARY OF BACKGROUND DATA: In previous studies, the full mobility of the lumbar segments has been investigated. The details of motion commonly seen with the activities of daily living have not been clarified. It has been reported that the iliolumbar ligaments have an influence on lumbosacral stability and that the relative thickness of the transverse process of L5 could indicate the functional strength of the iliolumbar ligaments. However, the effects of the iliolumbar ligaments on the lumbosacral range of motion have not been studied in vivo. METHODS: Ninety adults, aged 20-39 years, were requested to perform motion commonly associated with activities of daily living, defined as moderate motions of the lumbar spine. The subjects then were asked to perform maximal motion of the lumbar spine. The segmental ranges of motion, segmental flexion, and extension at every level of the lumbar spine were calculated by using functional radiographs. The correlation between the relative thickness of the transverse process of L5 and the motion seen at the lumbosacral junction was also determined. RESULTS: The greatest segmental range of motion was found at L2-L3 in moderate motion and at L4-L5 in maximal motion. It shifted gradually from the upper to lower lumbar levels with the increase in total lumbar motion. With an increase in lumbar spine motion, maximum segmental flexion shifted from L2-L3 to L3-L4, then to L4-L5. Segmental extension changed only at L5-S1, increasing with total lumbar spine motion. There was an inverse statistical correlation between lumbosacral motion and relative thickness of the L5 transverse process. CONCLUSIONS: The greatest segmental flexibility induced by the moderate lumbar motion, usually seen with the activities of daily living, occurred more in the upper segments of the lumbar spine, especially in flexion. Further, the iliolumbar ligaments regulate lumbosacral motion especially flexion.     

Anterolateral retroperitoneal psoas-sparing lumbar interbody fusion outcomes

ObjectiveAnterolateral Retroperitoneal Psoas-sparing, Anterior to Psoas (ATP) or oblique lateral interbody fusion (OLIF) is a psoas sparing technique postulated to decrease iatrogenic lumbar plexus injury. The goal of this paper is to assess the outcomes of the OLIF interbody fusion technique.ResultsOLIF procedures have a high rate of fusion with a low rate of complications particularly from L2-L5. Complications are more common, although still low, from L5-S1, primarily including cage subsidence and vascular injury.ConclusionThe Anterolateral Retroperitoneal Psoas-sparing approach to lumbar interbody fusion is a safe approach with a low complication and high fusion rate, resulting in excellent clinical and radiographic outcomes.     

Pelvic fixation: Biomechanics and complications

When extending a fusion construct to the sacrum in spinal deformity, there has long been difficulty in obtaining bony fusion at the L5-S1 level. This is due to a number of factors, including the altered morphology of the sacrum as compared to the lumbar vertebrae, adequate bone stock, and large cantilever forces at the lumbosacral junction, among others. This problem can be partially rectified by extending the construct to the pelvis, but even this does not result in a 100% fusion rate at the lumbosacral junction. The techniques currently used to fuse the spine to the pelvis primarily consist of iliac screws and S2 alar-iliac screws, but these techniques are not without complications. Here we review the biomechanics of pelvic fixation, techniques of these two screw types, and the complications associated with each.     

Minimum 2-year analysis of sacropelvic fixation and L5-S1 fusion using S1 and iliac screws

STUDY DESIGN: An analysis of lumbosacral fusions for high-grade spondylolisthesis fusions with reduction and long fusions to the sacrum in ambulatory adults. OBJECTIVE: To assess the clinical and radiographic results of lumbosacral fusions using bilateral S1 and iliac screws. SUMMARY OF BACKGROUND DATA: S1 screws often fail with lumbosacral fusions, whereas L5-S1 pseudarthrosis is common in patients with deformity. MATERIALS AND METHODS: A total of 81 patients (38 revision, 43 primary) with minimum 2-year follow-up (average, 4.2 years; range, 2.0-7.1 years) underwent L5-S1 fusion using S1 and iliac screws (158 screws). Forty-nine of 81 constructs (61%) included an anterior load-sharing/fixation device. Group 1 included isthmic spondylolisthesis (n = 42), whereas Group 2 included long fusions (> or =3 levels) to the sacrum (n = 39). In Group 2, 15 patients (Group 2A) were fused from L1, L2, or L3 to the sacrum (3-5 levels, average 3.3 levels) and 24 patients (Group 2B) were fused from the thoracic spine to the sacrum (6-17 levels, average 11.5 levels). Twelve patients had pseudarthrosis at L5-S1. A patient questionnaire was completed. RESULTS: A total of 36 of the 38 revision patients had previous iliac crest harvesting, yet iliac screws were placed in 34 of 36 patients. Overall, 78 of 80 patients had iliac crest harvesting (one not attempted). None had loss of screw fixation or iliac crest fracture after harvesting. Four of the 81 patients (4.9%) had pseudarthrosis at L5-S1 after reconstruction. This included solid fusion in 10 of 12 patients presenting with L5-S1 pseudarthrosis. Fourteen percent of patients experienced some discomfort over the iliac screws; however, only one patient required screw removal. CONCLUSIONS: Bilateral iliac screws coupled with bilateral S1 screws provide excellent distal fixation for lumbosacral fusions with a high fusion rate (95.1%) in high-grade spondylolisthesis and long fusions to the sacrum. Previous iliac crest harvesting does not prevent ipsilateral screw placement (34 of 36 patients) or additional iliac harvesting (78 of 80 patients).     

Role of the Lumbosacral Transition Vertebra and Vertebral Lamina in the Pathogenesis of Lumbar Disc Herniation

ObjectiveTo investigate the prevalence of lumbosacral transition vertebrae (LSTVs) in both the normal population and the lumbar disc herniation (LDH) population and to determine the risk factors for LDH.MethodsBetween January 2019 and September 2020, all patients aged 18–39 years and underwent an anteroposterior (AP) X‐ray of the lumbar vertebrae were retrospective reviewed in our institution. Those patients who were diagnosed with LDH were eligible for inclusion in the LDH group. During the same period, those patients admitted to our hospital who underwent an anteroposterior X‐ray of the lumbar spine and had not been diagnosed with LDH were included in the control group. Those patients with disease that might affect the lumbar anatomy were excluded from both groups. The type of LSTV was classified according to the Castellvi classification. The height of the lumbar vertebral lamina was evaluated through the h/H index. The inter‐ and intra‐observer reliability was evaluated by one senior radiologist and one senior orthopedist using intraclass correlation coefficient (ICC). The association between the LSTV and the herniation level was also investigated. Binary logistic regression was used to explore the association of different factors between the LDH group and the control group.ResultsTwo hundred LDH patients (115 male and 85 female) and 200 individuals (108 male and 92 female) were investigated retrospectively. The prevalence of LSTVs was 71.5% (n = 143) in the LDH group and 34.0% (n = 68) in the control group. The most frequent LSTV types were type Ib and type IIa. The inter‐ and intra‐observer ICCs of the measurement of “h/H” index and the classification of LSTV were all “excellent” (ICC > 0.90). The median h/H index in the control group was significantly higher than that in the LDH group (0.28 (0.26, 0.31) vs 0.34 (0.31, 0.37), P = 0.000). The distribution of the Castellvi classification in the L4/5 and L5/S1 herniation patients was significantly different (P = 0.048). LSTVs, BMI and the h/H index were closely associated with LDH, with odds ratios of 3.06 (95% CI: 2.12–4.43), 1.23 (95% CI: 1.13–1.33) and 0.09 (95% CI: 0.05–0.15), respectively. The incidence of L4/5 disc herniation in patients with an LSTV was significantly more common than that in patients with L5/S1 disc herniation (P = 0.048).ConclusionThe prevalence of LSTVs was 34.0% in the control group and 71.5% in the LDH group; LSTVs and BMI were positively correlated with LDH, and h/H was negatively correlated with LDH.     

Effect of major axial skeleton trauma on preexisting lumbosacral spondylolisthesis.

The incidental occurrence of lumbar spine fractures in individuals with preexisting first degree lumbosacral isthmic spondylolisthesis may be looked upon as a simulated in vivo biomechanical experiment testing the stability of the lumbosacral subluxation. Among 200 patients with thoracolumbar spine fractures managed at the author's institution during the period of 1980-1989, five such cases were collected. All patients had a grade I isthmic spondylolisthesis at the L5-S1 level, and all sustained a burst fracture of the lumbar spine. In two patients, there was a previous history of low back pain and lumbosacral spondylolisthesis. In the other three patients, the olisthesis was judged to be old by a negative 99mTc-MDP bone scan, whereas the fractured vertebra showed intense uptake and/or by the negative operative findings at L5-S1 level during surgery. It was found that the incidence of lumbosacral spondylolisthesis in patients with thoracolumbar fractures was smaller than in the general population but the difference was not statistically significant (p = 0.213). In addition, it is concluded that mild lumbosacral spondylolisthesis can absorb considerable axial loading without an ascertainable evidence of damage.     

Nuances of oblique lumbar interbody fusion at L5-S1: Three case reports

BACKGROUNDOblique lumbar interbody fusion is a mini-open retroperitoneal approach that uses a wide corridor between the left psoas muscle and the aorta above L5. This approach avoids the limitations of lateral lumbar interbody fusion, is considered less invasive than anterior lumbar interbody fusion, and is similarly effective for indirect decompression and improving lordosis while maintaining a low complication profile. Including L5-S1, when required, adds to these advantages, as this allows single-position surgery. However, variations in vascular anatomy can affect the ease of access to the L5-S1 disc. The nuances of three different oblique anterolateral techniques to access L5-S1 for interbody fusion, namely, left-sided intra-bifurcation, left-sided pre-psoas, and right-sided pre-psoas approaches, are illustrated using three representative case studies.CASE SUMMARYCases of three patients who underwent multilevel oblique lumbar interbody fusion including L5-S1, using one of the three different techniques, are described. All patients presented with symptomatic degenerative lumbar pathology and failed conservative management prior to surgery. The anatomical considerations that affected the decisions to utilize each approach are discussed. The pros and cons of each approach are also discussed. A parasagittal facet line objectively assesses the relationship between the left common iliac vein and the L5-S1 disc and assists in choosing the approach to L5-S1.CONCLUSIONOblique retroperitoneal access to L5-S1 in the lateral decubitus position is possible through three different approaches. The choice of approach to L5-S1 may be individualized based on a patient’s vascular anatomy using preoperative imaging. While most surgeons will rely on their experience and comfort level in choosing the approach, this article elucidates the nuances of each technique.     

Single-level controlled comparison of OLIF51 and percutaneous screw in lateral position versus MIS-TLIF for lumbosacral degenerative disorders: Clinical and radiologic study

BackgroundWe have performed minimally invasive Oblique Lateral Interbody Fusion at L5/S1 (OLIF51) and simultaneous posterior screwing in lateral position for lumbosacral disorders. This study compared the clinical and radiologic results between OLIF51 versus Minimally Invasive Transforaminal Lumbar Interbody Fusion (MIS-TLIF) in single-level fusion for lumbosacral degenerative disorders.MethodsA total of 71 patients underwent either OLIF51 (33 cases) or MIS-TLIF (38 cases) at L5/S1 spinal segment. The average age was 64 yrs (27–88). The disorders were L5 isthmic or degenerative spondylolisthesis, foraminal stenosis, pseudarthrosis and adjacent segment degeneration, and others. Using 35 mm oblique incision, OLIF51 was performed followed by posterior percutaneous fixation in same lateral position. MIS-TLIF was performed with midline 40 mm incision and modified cortical bone trajectory (CBT) screws. The operation time, estimated blood loss, JOABPEQ effectiveness rate (%), Visual Analogue Scale (VAS), fusion rate, radiologic alignment, and complications were evaluated.ResultsAverage follow-up period was 25 and 31 months (12–45) in OLIF51 and MIS-TLIF, respectively. The average operation time and estimated blood loss were 165min, 62 ml and 163 min and 68 ml, respectively. The JOABPEQ effectiveness rate in OLIF51 demonstrated higher value in low back function (44% vs 17%, P < 0.02). The fusion rate was 97% and 92% in OLIF51 and MIS-TLIF, respectively. The segmental lordosis was significantly larger in OLIF51 (17 vs 11 deg, P < 0.01). There were no vascular or neural complications.ConclusionsAlthough two groups demonstrated the equivalent surgical invasiveness, there was the significant superiority of OLIF51 in terms of low back function over MIS-TLIF. The segmental lordosis creation was also better in OLIF51. Even in the single-level lumbosacral fusion, OLIF51 serves as the safe and viable surgical procedure with use of lateral position surgery, minimizing the residual low back dysfunction.     

腰脊柱构型与椎间盘突出症的关系

本文复习了２０５例已手术治疗的腰椎间盘突出的症病人的术前Ｘ线表现，结果提示深 Ｌ５发生Ｌ４－５椎间盘突出的可能性增高，而高骑Ｌ５则与Ｌ５－Ｓ１椎间盘出有关，腰骶移行椎的发生率较正常人显著增高，而腰骶角的病理意义尚难确定。     

Determining the lumbar vertebral segments on magnetic resonance imaging.

STUDY DESIGN: A study to test the ability of an additional cervicothoracic localizer scan to decrease interobserver discrepancy in the identification of vertebral segments in magnetic resonance imaging of the lumbar spine. OBJECTIVES: To investigate whether lumbar vertebral segments can be identified correctly from lumbosacral magnetic resonance localizer scans, the degree of interobserver discrepancy, and the value of an additional cervicothoracic localizer scan. SUMMARY OF BACKGROUND DATA: In magnetic resonance imaging of the lumbar spine, it may be difficult to identify transitional lumbosacral vertebral segments. METHODS: The sagittal and coronal lumbosacral localizer scans of 141 consecutive patients referred for magnetic resonance imaging of the lumbosacral spine were reviewed independently by two radiologists with the aim of locating the L5 vertebra. An additional sagittal cervicothoracic localizer scan also was performed in each case. The final study group consisted of 129 patients. The L5 vertebra was identified by counting caudally from C2 using the sagittal cervicothoracic and lumbosacral localizer scans. In the 54 most recently studied patients, cod liver oil capsule surface markers were placed near the thoracolumbar junction to quantify any marker shift between the two sagittal localizer scans. RESULTS: The lumbar segments could be identified consistently by counting caudally using cervicothoracic and lumbosacral localizer scans. Using sagittal lumbosacral localizer scans alone, the lumbar vertebral segments could be identified correctly in only 80.2% of patients. Coronal lumbosacral localizer scans produced similar results (82.2%). The accuracy fell to 77.9% when using a combination of both sagittal and coronal lumbosacral localizer scans. There was a 11.6% interobserver discordance in assessment of these levels. Lumbosacral transitional vertebrae were identified in 17 patients (13.2%), including 8 sacralized L5 and 9 lumbarized S1 vertebrae. Apparent surface-marker shift between cervicothoracic and lumbosacral localizer scans was insignificant, averaging only 1.9 mm (range, 0.0-5.6 mm). CONCLUSIONS: The addition of a cervicothoracic localizer scan in magnetic resonance imaging of the lumbosacral spine is highly recommended.     

The prevalence of transitional vertebrae in the lumbar spine

Background context

Lumbosacral transitional vertebrae (LSTVs) are a congenital vertebral anomaly of the L5–S1 junction in the spine. This alteration may contribute to incorrect identification of a vertebral segment, leading to wrong-level spine surgery and poor correlation with clinical symptoms. Although several studies describe the occurrence of this anomaly in back pain populations, investigation of the prevalence in the American general population is lacking.

Purpose

To establish the prevalence rates for LSTVs in the general population.

Study design

Retrospective review.

Patient sample

Consecutive kidney-urinary bladder (KUB) radiographs of subjects from the past 2 years (2008–2009).

Outcome measures

Clinical demographics, number of lumbar vertebrae, L5–S1 transverse process (TP) height, and rib length.

Methods

Consecutive adult KUB studies of adult subjects were queried with clear visibility of the last rib’s vertebral body articulation, all lumbar TPs, and complete sacral wings. Exclusion criteria consisted of any radiologic evidence of previous lumbosacral surgery that would obstruct our measurements. A total of 1,100 abdominal films were reviewed, and 211 were identified as being adequate for the measurement of the desired parameters.

Results

Two hundred eleven subjects were identified as eligible for the study, and 75 (35.6%) were classified as positive for a transitional lumbosacral vertebra. The most common anatomical variant was the Castellvi Type IA (14.7%). The average age at the time of the KUB study was 59.8 years (18–95 years). One hundred ninety-seven subjects (93.4%) presented five lumbar (nonribbed) vertebrae, and only 14 (6.6%) had six lumbar vertebrae.

Conclusions

The significance of lumbosacral transitional level changes to the establishment of pain, degenerative changes, stenosis, and disc disease have been well documented in symptomatic patients. Although LSTV’s role in low back pain remains controversial, our study has shown that, when the same criteria are used for classification, prevalence among the general population and symptomatic patients may be similar.     

Lumbosacral metastatic extradural Merkel cell carcinoma causing nerve root compression--case report

A 63-year-old man presented with a rare metastatic Merkel cell carcinoma (MCC) involving the lumbosacral spine and causing nerve root compression. Magnetic resonance (MR) imaging revealed an extradural soft tissue mass at the L5-S1 levels. The tumor was subtotally removed and chemotherapy was administered, but he died of multiple metastases from the primary epigastric tumor. Lumbosacral metastatic epidural tumor can manifest as lumbar disc disease symptoms, but MR imaging can non-invasively and rapidly reveal the presence of spinal epidural tumor and any extension to the spinal canal. Extradural MCC metastasis in the lumbosacral area should be considered in the differential diagnosis of radicular symptoms caused by disc herniation.     

Total L-5 spondylectomy and reconstruction of the lumbosacral junction. Technical note

The authors describe a technique for total L-5 spondylectomy and reconstruction of the lumbosacral junction. The technique, which involves separately staged posterior and anterior procedures, is reported in two patients harboring neoplasms that involved the L-5 level. The first stage consisted of a posterior approach with removal of all posterior bone elements of L-5 and radical L4-5 and L5-S 1 discectomies. Lumbosacral and lumbopelvic instrumentation included pedicle screws as well as iliac screws or a transiliac rod. The second stage consisted of an anterior approach with mobilization of vascular structures, completion of L4-5 and L5-S1 discectomies, and removal of the L-5 vertebral body. Anterior lumbosacral reconstruction included placement of a distractable cage and tension band between L-4 and S-1. Allograft bone was used for fusion in both stages. No significant complications were encountered. At more than 1 year of follow-up, both patients were independently ambulatory, without evidence of recurrent or metastatic disease, and adequate lumbosacral alignment was maintained. The authors conclude that this technique can be safely performed in appropriately selected patients with neoplasms involving L-5.     

Indirect decompression via oblique lateral interbody fusion for severe degenerative lumbar spinal stenosis: a comparative study with direct decompression transforaminal/posterior lumbar interbody fusion

Background contextPrevious studies have shown that oblique lateral interbody fusion (OLIF) can improve neurological symptoms via “indirect decompression.” However, data are lacking in terms of its benefits when compared with conventional transforaminal lumbar interbody fusion (TLIF) and/or posterior lumbar interbody fusion (PLIF) approach, especially in patients with severe central canal stenosis.PurposeTo investigate the clinical outcome of OLIF without posterior decompression versus conventional TLIF and/or PLIF in severe lumbar stenosis diagnosed on preoperative magnetic resonance imaging.Study designRetrospective comparative study.Patient sampleFifty-one patients who underwent OLIF and 41 patients who underwent conventional TLIF and/or PLIF.Outcome measuresClinical outcome score by Japanese Orthopedic Association (JOA) score and radiographic outcomes (disc height and fusion rate on computed tomography scan).Materials/methodsWe retrospectively reviewed 51 patients who underwent OLIF with supplemental percutaneous pedicle screws (55 levels; OLIF group) and 41 patients who underwent conventional TLIF and/or PLIF (47 levels; TPLIF group). The cross-sectional area of the thecal sac was measured preoperatively in OLIF and TPLIF groups, but postoperatively only in the OLIF group. All patients were diagnosed with severe stenosis based on Schizas classification (Grade C or D) on magnetic resonance imaging. We compared radiographic and clinical outcome scores (JOA score) between the 2 groups at 1 year of follow-up. The radiographic evaluation included the fusion status and disc height on computed tomography scan. Surgical data and perioperative complications were also investigated.ResultsThe baseline demographic data of the 2 groups were equivalent in preoperative diagnosis, JOA score, and disc height and/or angle. The cross-sectional area significantly increased postoperatively, which confirmed indirect decompressive effect in the OLIF group. The JOA score improved in both groups at the 1-year follow up (76.6% vs. 73.5% improvement rate in the OLIF and TPLIF groups, respectively). The fusion rate at the 1-year follow-up was higher in the OLIF group than in the TPLIF group (87.2% vs. 57.4%). The disc height restoration was also better in the OLIF group. The operative data demonstrated less estimated blood loss and operative time in the OLIF group.ConclusionsOLIF and conventional TLIF and/or PLIF demonstrated comparable short-term clinical outcomes in the treatment of severe degenerative lumbar stenosis. However, the surgical and radiographic outcomes were better in the OLIF group. Surgeons should choose an appropriate approach on a case by case basis, recognizing the perioperative complications specific to each fusion procedure.