L5 S1 Research Articles

143. Determining the best vertebra for measuring pelvic incidence and spinopelvic parameters in transitional anatomy

<h3>BACKGROUND CONTEXT</h3> Sacralization of L5 is a condition that affects 15% of the population. Because of the increased L5 articulations to the sacrum, it is unclear how pelvic incidence and spinopelvic parameters should be measured. <h3>PURPOSE</h3> Determine whether patients with L5 sacralization should be radiographically measured with relation to the L5 or S1 vertebrae. <h3>STUDY DESIGN/SETTING</h3> Retrospective analysis. <h3>PATIENT SAMPLE</h3> Prospective multicenter adult spinal deformity database. <h3>OUTCOME MEASURES</h3> ODI, SF36 PCS, radiographic spinopelvic parameters. <h3>METHODS</h3> Linear regression modeling was used to determine normative TPA and PI-LL based on PI and age in a database of asymptomatic subjects. In an adult spinal deformity database, patients with radiographic evidence of L5 sacralization, had PI, LL and TPA measured from the superior endplate S1 and then also from L5. Patients with instrumentation below L4 at baseline were excluded. The differences in TPA and PI-LL from normative were calculated in the sacralization cohort relative to L5 and S1 and correlated to ODI. Patients were grouped based on PI-LL Schwab modifier (0, +, ++) utilizing their L5 PI-LL and S1 PI-LL. Baseline ODI and SF36 PCS were compared across and within groups and their respective SRS Schwab class. <h3>RESULTS</h3> Among 1,179 ASD patients, 276 (23.4%) had transitional anatomy, 176 with sacralized L5 (14.9%) and 100 (8.48%) with lumbarization of S1. The 176 with sacralized L5 were analyzed. PI (24.5 ± 11.0 vs 55.7 ± 12.0, p=0.001), TPA (11.2 ± 12.0 vs 20.3 ± 12.5, p=0.001) and PI-LL (0.67 ± 21.1 vs 11.4 ± 20.8, p=0.001) measured utilizing the L5 superior endplate were significantly smaller than those who were measured relative to S1. When measured from S1, 76 (43. %) of patients were SRS Schwab 0, 45 (25.6%) were Class +, and 55 (31.3%) were class ++ compared to 124 (70.5%), 22 (12.5%), and 30 (17.0%) measured from L5 respectively. There were significant differences in ODI and PCS as the Schwab grade increased regardless of L5 or S1 measurement. The L5 group had higher PCS functional scores for Schwab 0 and ++ relative to same grades in the S1 group. Offset from normative TPA (0.5 ± 11.1 vs 9.6 ± 10.8, p=0.001) and PI-LL (0.67 ± 21.1 vs 11.4 ± 20.8, p=0.001) were smaller when measuring from L5. Moreover, S1 measurements were more correlated with disability by ODI (TPA offset from normative, S1: R=0.326 vs L5: R=0.285; PI-LL Offset from normative, S1: R=0.318 vs L5: R=0.274). <h3>CONCLUSIONS</h3> Measuring the PI at L5 in sacralized anatomy results in underestimating the PILL Schwab grade in a percentage of patients and less correlation with HRQLs. Patients with sacralized L5s should have spinopelvic parameters measured relative to S1. <h3>FDA DEVICE/DRUG STATUS</h3> This abstract does not discuss or include any applicable devices or drugs.

Navigation-assisted resection of tumoral calcinosis of the lumbosacral spine: illustrative case

BACKGROUNDTumoral calcinosis is an uncommon disease resulting from dystrophic calcium phosphate crystal deposition, with only 7% of cases involving the spine, and it may diagnostically mimic neoplasms.OBSERVATIONSIn this case, a 54-year-old woman with history of systemic scleroderma presented with 10 months of progressive left lumbosacral pain. Imaging revealed an expansile, 4 × 7-cm, well-circumscribed mass in the lumbosacral spine with L5–S1 neuroforaminal compression. Because intractable pain and computed tomography (CT)-guided needle biopsy did not entirely rule out malignancy, operative management was pursued. The patient underwent L4–S2 laminectomies, left L5–S1 facetectomy, L5 and S1 pediculectomies, and en bloc resection, performed under stereotactic CT-guided intraoperative navigation. Subsequently, instrumented fusion was performed with L4 and L5 pedicle screws and S2 alar-iliac screws. Pathological examination was consistent with tumoral calcinosis, with multiple nodules of amorphous basophilic granular calcified material lined by histiocytes. There was no evidence of recurrence or neurological deficits at 5-month follow-up.LESSONSBecause spinal tumoral calcinosis may mimic neoplasms on imaging or gross intraoperative appearance, awareness of this clinical entity is essential for any spine surgeon. A review of all case reports of lumbosacral tumoral calcinosis (n = 14 from 1952 to 2016) was additionally performed. The case featured in this report presents the first known case of navigation-assisted resection of lumbosacral tumoral calcinosis.

LUMBAR DISK HERNIATION: EVALUATION OF MEDICAL CARE AND PAIN MANAGEMENT AT THE SPECIALTIES HOSPITAL CREHVITAL AMBATO-ECUADOR: RETROSPECTIVE, CROSS-SECTIONAL STUDY, AND ASSESSMENT OF TWO CLINICAL CASES

Objectives: The objective of the study was to assess medical care and pain management of 237 lumbar disk herniation cases treated from 2011 to 2021 in the Specialties Hospital CREHVITAL, Ambato-Ecuador, and to provide a set of standards for appropriate management. Methods: Retrospective, cross-sectional analysis of archives, and registries of patient’s data provided by the Specialties Hospital CREHVITAL, Ambato-Ecuador. Participants: A total of 237 patients with lumbar disk herniation received medical services from 2011 to 2021; outcome measures were: Pain management, patient characteristics, surgical procedures, and medication after surgery. Results: The 40–50 age range had the highest prevalence of lumbar disk herniation and a higher percentage of the pathology in men (66%) than in women. Of the 237 patients, magnetic resonance imaging (MRI) showed the highest lumbar disk herniation of the L4–L5 (101 men and 20 women), followed by herniation of the L5–S1 (59 men and 51 women). Two types of surgeries were performed: Classical surgery on 157 patients and microsurgery on 80 patients. The average period before receiving treatment was 1.5 years of maintaining back pain, and the early post-operative management consisted of patients receiving diclofenac, ketorolac, and ceftriaxone. Analgesics were used in 73.43% of patients. All cases required strict control, follow-up, and post-operative check-ups. Conclusion: This study provides essential and conclusive evidence and information on treated cases of lumbar disk herniation and its incidence in the medical field.

Results of Lumbar Transpedicular Fixation for Spondycolisthesis, in Terms of Back Pain Relief

Objective: The goal of this study was to see how transpedicular fixation for degenerative spondylolisthesis affected lumbago.&#x0D; Methodology: A retrospective observational study was conducted at the Department of Neurosurgery in Hayatabad Medical Complex, Peshawar between May 2018 and February 2020. Degenerative spondylolisthesis was diagnosed using static and dynamic spinal X-rays. The research excluded the patients with grade 5 spondylolisthesis, congenital anomalies, or prior spinal surgery. The visual rating scale was used to assess pain alleviation (GRS). Dynamic or static lumbosacral X-rays and 3D CT scans were used to assess union.&#x0D; Results: In total 70 patients, 38 (54.3%) were male and 32 (45.7%) were female. L5–S1 was impacted in most of the cases (68%). 40% of patients were having Meyerding grade II. All patients had pedicle screw fixation. Following surgery, 44 (63%) patients reported no pain, and 12 (17%) patients reported mild discomfort. 8 (11%) patients reported moderate pain and 6(9%) patients experienced severe pain. There existed a significant difference between pre/postoperative moderate-severe GRS scores (p-value: 0.000336). After surgery, we were able to negotiate surgical unions with 91.4% of the patients.&#x0D; Conclusion: For individuals with spondylolisthesis who need pain relief, transpedicular fixation is a safe, straightforward, and effective treatment. It also aids with the surgical union and the improvement of the neurological condition.&#x0D; Keywords: Spondylolisthesis, Meyerding grading, Transpedicular fixation.

Biomechanical study of rod stress in lumbopelvic fixation with lateral interbody fusion: an in vitro experimental study using synthetic bone models.

Despite improvements in surgical techniques and instruments, high rates of rod fracture following a long spinal fusion in the treatment of adult spinal deformity (ASD) remain a concern. Thus, an improved understanding of rod fracture may be valuable for better surgical planning. The authors aimed to investigate mechanical stress on posterior rods in lumbopelvic fixation for the treatment of ASD. Synthetic lumbopelvic bone models were instrumented with intervertebral cages, pedicle screws, S2-alar-iliac screws, and rods. The construct was then placed in a testing device, and compressive loads were applied. Subsequently, the strain on the rods was measured using strain gauges on the dorsal aspect of each rod. When the models were instrumented using titanium alloy rods at 30° lumbar lordosis and with lateral interbody fusion cages, posterior rod strain was highest at the lowest segment (L5-S1) and significantly higher than that at the upper segment (L2-3) (p = 0.002). Changing the rod contour from 30° to 50° caused a 36% increase in strain at L5-S1 (p = 0.009). Changing the rod material from titanium alloy to cobalt-chromium caused a 140% increase in strain at L2-3 (p = 0.009) and a 28% decrease in strain at L5-S1 (p = 0.016). The rod strain at L5-S1 using a flat bender for contouring was 23% less than that obtained using a French bender (p = 0.016). In lumbopelvic fixation in which currently available surgical techniques for ASD are used, the posterior rod strain was highest at the lumbosacral junction, and depended on the contour and material of the rods.

Correction of sagittal imbalance after previous surgical interventions for degenerative lumbar spine disease

Objective. To analyze clinical and radiological results of corrective fusion in the lumbar spine in the treatment of patients with sagittal imbalance after previous surgical interventions.Material and Methods. A retrospective monocentric study, clinical case series. The data of 18 patients operated on using a combination of surgical methods with obligatory anterior corrective fusion at the L4–L5 and/or L5–S1 levels to achieve optimal parameters of the sagittal balance disturbed or developed after previous interventions were analyzed. Clinical and radiological parameters were assessed during hospital stay and at least 10 months later.Results. The study presents data from 3 (16.7 %) men and 15 (83.3 %) women with an average age of 57.5 ± 9.1 years. Average length of hospital stay was 26.9 ± 10.1 days. In 7 (38.9 %) cases, the deformity occurred at the previously operated level and in 11 (61.1 %) – at the adjacent one. The duration of surgery was 481.4 ± 101.7 minutes, and blood loss was 1028.9 ± 594.9 ml. Back and leg pain VAS scores decreased in 10–19 months after surgery from 6.4 ± 0.9 and 4.8 ± 1.3 to 3.2 ± 1.2 and 0.9 ± 0.8, respectively (p &lt; 0.001). The ODI score decreased from 59.6 ± 5.9 to 39.9 ± 7.7 (p &lt; 0.001). The ideal Roussouly type was restored in 11 (61.1 %) cases, below ideal – in 3 (16.7 %), and overcorrection – in 4 (22.2 %). LL increased from 48.1 ± 13.6 ° to 56.9 ± 11.6 ° (p &lt; 0.001), and LDI – from 40.1 ± 16.9 to 58.8 ± 10.3 (p &lt;0.001); SVA decreased from 5.1 ± 1.9 to 3.4 ± 2.1 cm (p &lt; 0.001), PT – from 23.9° ± 7.2° to 19.1° ± 3.8° (p &lt; 0.001). According to GAP score, the number of patients with severe and moderate disproportion was reduced (p &lt; 0.001). Perioperative complications were observed in 12 (66.7 %) patients.Conclusion. Multi-stage surgical correction of the residual and aggravated sagittal imbalance with obligatory anterior corrective interbody fusion after instrumental correction of degenerative spinal deformity through the posterior approach significantly improves clinical and radiological parameters and allows restoring a harmonious sagittal profile in 61.1 % of cases.

Assessment of L5-S1 anterior lumbar interbody fusion stability in the setting of lengthening posterior instrumentation constructs: a cadaveric biomechanical study.

Excessive stress and motion at the L5-S1 level can lead to degenerative changes, especially in patients with posterior instrumentation suprajacent to L5. Attention has turned to utilization of L5-S1 anterior lumbar interbody fusion (ALIF) to stabilize the lumbosacral junction. However, questions remain regarding the effectiveness of stand-alone ALIF in the setting of prior posterior instrumented fusions terminating at L5. The purpose of this study was to assess the biomechanical stability of an L5-S1 ALIF with increasing lengths of posterior thoracolumbar constructs. Seven human cadaveric spines (T9-sacrum) were instrumented with pedicle screws from T10 to L5 and mounted to a 6 degrees-of-freedom robot. Posterior fusion construct lengths (T10-L5, T12-L5, L2-5, and L4-5) were instrumented to each specimen, and torque-fusion level relationships were determined for each construct in flexion-extension, axial rotation, and lateral bending. A stand-alone L5-S1 ALIF was then instrumented, and L5-S1 motion was measured as increasing pure moments (2 to 12 Nm) were applied. Motion reduction was calculated by comparing L5-S1 motion across the ALIF and non-ALIF states. The average motion at L5-S1 in axial rotation, flexion-extension, and lateral bending was assessed for each fusion construct with and without ALIF. After adding ALIF to a posterior fusion, L5-S1 motion was significantly reduced relative to the non-ALIF state in all but one fused surgical condition (p < 0.05). Longer fusions with ALIF produced larger L5-S1 motions, and in some cases resulted in motions higher than native state motion. Posterior fusion constructs up to L4-5 could be appropriately stabilized by a stand-alone L5-S1 ALIF when using a nominal threshold of 80% reduction in native motion as a potential positive indicator of fusion. The results of this study allow conclusions to be drawn from a biomechanical standpoint; however, the clinical implications of these data are not well defined. These findings, when taken in appropriate clinical context, can be used to better guide clinicians seeking to treat L5-S1 pathology in patients with prior posterior thoracolumbar constructs.

Influence of Sagittal Lumbopelvic Morphotypes on the Range of Motion of Human Lumbar Spine: An In Vitro Cadaveric Study.

Background: Although spinopelvic radiographs analysis is the standard for a pathological diagnosis, it cannot explain the activities of the spine in daily life. This study investigates the correlation between sagittal parameters and spinal range of motion (ROM) to find morphological parameters with kinetic implications. Methods: Six L1–S1 human lumbar specimens were tested with a robotic testing device. Eight sagittal parameters were measured in the three-dimensional model. Pure moments were applied to simulate the physiological activities in daily life. Results: The correlation between sagittal parameters and the ROM was moderate in flexion and extension, but weak in lateral bending and rotation. In flexion–extension, the ROM was moderately correlated with SS and LL. SS was the only parameter correlated with the ROM under all loading conditions. The intervertebral rotation distribution showed that the maximal ROM frequently occurred at the L5–S1 segment. The minimal ROM often appeared near the apex point of the lumbar. Conclusion: Sagittal alignment mainly affected the ROM of the lumbar in flexion and extension. SS and apex may have had kinetic significance. Our findings suggest that the effect of sagittal parameters on lumbar ROM is important information for assessing spinal activity.

Radiographic comparison of lordotic and hyperlordotic implants in L5-S1 anterior lumbar interbody fusion.

Anterior lumbar interbody fusion (ALIF) used at the lumbosacral junction provides arthrodesis for several indications. The anterior approach allows restoration of lumbar lordosis, an important goal of surgery. With hyperlordotic ALIF implants, several options may be employed to obtain the desired amount of lordosis. In this study, the authors compared the degree of radiographic lordosis achieved with lordotic and hyperlordotic ALIF implants at the L5-S1 segment. All patients undergoing L5-S1 ALIF from 2 institutions over a 4-year interval were included. Patients < 18 years of age or those with any posterior decompression or osteotomy were excluded. ALIF implants in the lordotic group had 8° or 12° of inherent lordosis, whereas implants in the hyperlordotic group had 20° or 30° of lordosis. Upright standing radiographs were used to determine all radiographic parameters, including lumbar lordosis, segmental lordosis, disc space lordosis, and disc space height. Separate analyses were performed for patients who underwent single-segment fixation at L5-S1 and for the overall cohort. A total of 204 patients were included (hyperlordotic group, 93 [45.6%]; lordotic group, 111 [54.4%]). Single-segment ALIF at L5-S1 was performed in 74 patients (hyperlordotic group, 27 [36.5%]; lordotic group, 47 [63.5%]). The overall mean ± SD age was 61.9 ± 12.3 years; 58.3% of patients (n = 119) were women. The mean number of total segments fused was 3.2 ± 2.6. Overall, 66.7% (n = 136) of patients had supine surgery and 33.3% (n = 68) had lateral surgery. Supine positioning was significantly more common in the hyperlordotic group than in the lordotic group (83.9% [78/93] vs 52.3% [58/111], p < 0.001). After adjusting for differences in surgical positioning, the change in lumbar lordosis was significantly greater for hyperlordotic versus lordotic implants (3.6° ± 7.5° vs 0.4° ± 7.5°, p = 0.048) in patients with single-level fusion. For patients receiving hyperlordotic versus lordotic implants, changes were also significantly greater for segmental lordosis (12.4° ± 7.5° vs 8.4° ± 4.9°, p = 0.03) and disc space lordosis (15.3° ± 5.4° vs 9.3° ± 5.8°, p < 0.001) after single-level fusion at L5-S1. The change in disc space height was similar for these 2 groups (p = 0.23). Hyperlordotic implants provided a greater degree of overall lumbar lordosis restoration as well as L5-S1 segmental and disc space lordosis restoration than lordotic implants. The change in disc space height was similar. Differences in lateral and supine positioning did not affect these parameters.

Minimally Invasive versus Conventional Lumbar Interbody Fusion at L5–S1: A Retrospective Comparative Study

Objective: This study aimed to evaluate the radiologic and clinical outcomes of minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF) and conventional posterior lumbar interbody fusion (PLIF) at the L5–S1.Methods: We retrospectively reviewed patients who underwent posterior lumbar fusion (MIS-TLIF and PLIF) at only the L5–S1 and were followed up for more than 12 months. Age, sex, body mass index (BMI), bone mineral density (BMD), diagnosis, comorbid conditions, fusion rate, perioperative results, and pre- and postoperative radiographic parameters at the L5–S1 level, pelvic parameters and degree of spondylolisthesis, and clinical results were analyzed.Results: A total of 102 patients (46 male, 56 female) with a mean age of 57.1 years were evaluated. Fifty and fifty-two patients underwent MIS-TLIF and PLIF surgeries, respectively. Radiologic parameters increased from their preoperative measures at the last follow-up study; similarly, there were no intergroup differences. The fusion rates in the MIS-TLIF and PLIF groups were 86% and 82.7%, respectively. The subsidence rates in the MIS-TLIF and PLIF groups were 6% and 3.8%, respectively. There was no intergroup difference in terms of fusion rate and subsidence. Clinical outcomes also gradually improved after surgery in both groups without intergroup differences.Conclusion: In L5–S1 posterior spinal surgery, there was no significant difference between MIS-TLIF and conventional PLIF. Considering the operation time and estimated blood loss, MIS-TLIF is more effective than PLIF surgery in terms of postoperative health care and economics.

Neurophysiological parameters in patients with hallux valgus

We examined 38 patients (35 women and 3 men aged 30–40 years) with stage 2 and 3 hallux valgus in the department of traumatology and orthopedics of the Irkutsk Scientific Centre of Surgery and Traumatology to study the electroneuromyographic parameters during stimulation of the peripheral nerves of the lower extremities. All patients underwent electroneuromyographic study of peripheral nerves (n. tibialis and n. peroneus) to clarify the nature of their injuries. In 10 patients, the parameters of the monosynaptic H-reflex were additionally studied. Analysis of electroneuromyographic parameters in patients with hallux valgus demonstrated a deterioration in the peripheral nerves functioning, which was more pronounced for the tibial nerve (n. tibialis). At the same time, the parameters of the monosynaptic H-reflex obtained in patients with hallux valgus indicate the presence of a neurological deficit observed in the compression of the L5–S1 roots of the spinal cord in lumbar osteochondrosis. The results of the study suggest the presence of a single pathogenetic mechanism for the development of degenerative processes in the spinal joints (osteochondrosis) and limbs (deforming osteoarthrosis of large and small joints).

Role of electromyography and ultrasonography in the diagnosis of double crush lumbar radiculopathy and common fibular injury: illustrative cases.

BACKGROUNDDouble crush syndrome consists of two compression sites along a peripheral nerve and is rare in the lower extremities. Electrodiagnostic and ultrasound (US) studies may be helpful in evaluating foot drop involving overlapping pathologies.OBSERVATIONSCase 1 involved a man who presented with left dorsiflexor weakness and left foot numbness. Electromyography (EMG) revealed a left common fibular nerve entrapment neuropathy and left L5 radiculopathy. US and magnetic resonance imaging (MRI) revealed a large cystic lesion of the left common fibular nerve treated by cyst removal. The left foot drop persisted postoperatively. Lumbar computed tomography myelography revealed severe left foraminal stenosis at L5–S1. Multilevel lumbar laminectomies and facetectomies with an L5–S1 fusion were performed. Within 1 month postoperatively, the left foot drop had improved. Case 2 involved a man who developed a right foot drop caused by right lumbar foraminal stenosis at L4–5 and L5–S1. EMG and US of the right common fibular neuropathy showed large fascicles involving the right common fibular nerve. MRI revealed a hyperintense signal of the right common fibular nerve. Spontaneous improvement occurred within 6 months without surgery.LESSONSSpine surgeons should recognize double crush in the lower extremities. EMG and US are valuable in detecting peripheral nerve abnormalities, especially in cases with overlapping lumbar pathology.

Relationship between facet joint opening on CT and facet joint effusion on MRI in patients with lumbar spinal stenosis: analysis of a less invasive decompression procedure.

Both facet joint opening (FJO) on CT and facet joint effusion (FJE) on MRI are reportedly indicators of segmental instability in the lumbar facet joints of patients with lumbar spinal stenosis (LSS). However, no study has investigated both parameters simultaneously. Therefore, the association between these findings and which parameter is better for predicting clinical outcomes after surgical treatment remains unclear. The purpose of this study was to investigate the relationship between FJO and FJE in patients who underwent less invasive decompression procedures for LSS and to investigate the impact of these findings on clinical outcomes. This study included 1465 lumbar levels (L1-2 to L5-S1) in 293 patients who underwent less invasive surgery for LSS and had ≥ 5 years of follow-up. FJO was defined as joint space widening ≥ 2 mm on preoperative axial CT images. FJE was defined as fluid effusion in the facet joint on preoperative axial T2-weighted MR images. The characteristics and distributions of FJO and FJE were investigated with other preoperative radiological findings. The association between need for further surgery and FJO/FJE was analyzed according to intervertebral level. FJO was observed at 402 levels (27%), and FJE was found at 306 levels (21%). The correspondence rate between FJO and FJE was 70% (kappa 0.195, p < 0.01). One hundred thirty-seven levels (9%) had both FJO and FJE. Levels with both FJO and FJE more commonly had lateral olisthesis, lateral wedging, and axial intervertebral rotation than other levels (p < 0.001). Levels with both FJO and FJE were more likely than other levels to need further surgery (OR 2.42, p = 0.027). The correspondence rate between FJO and FJE was not high. However, multivariate analysis showed that levels with both FJO and FJE had a higher risk of requiring further surgery than those with other radiological findings, such as lateral olisthesis, lateral wedging, and axial intervertebral rotation. Patients with levels with both FJO and FJE need careful long-term follow-up after undergoing a less invasive decompression procedure.

Assessment of technical adequacy of sacral lateral branches cooled radiofrequency neurotomy

ObjectiveThere were two primary objectives of the study: 1. assessment of the association between diagnostic sacral lateral branches (SLB) blocks and the ensuing numbness in the middle cluneal nerves (MCN) distribution, irrespective of whether the patients had positive or negative responses to blocks. 2. If the consistency of this causal relationship was established, we wanted to investigate a further correlation - hypoesthesia from local anesthetic blocks vs. hypoesthesia from radiofrequency neurotomy (RFN) vs. outcomes. DesignThis is a prospective observational study of sixty consecutive patients with sacroiliac (SI) joint complex pain and failure of previous intraarticular SI joint injection. The patients who had two positive diagnostic SLB blocks defined as ≥ 75% reduction in NRS scores were treated with cooled RFN of the L5 dorsal ramus and S1–S3 lateral branches. The patients were interviewed and evaluated at a one-month post-neurotomy follow-up appointment. Seven patients were also evaluated at a six-month follow-up visit after the procedure. MethodsThe primary outcomes of the study were absence/presence of post-procedural buttock hypoesthesia after diagnostic blocks and absence/presence of post-procedural buttock hypoesthesia at one month after a cooled RFN procedure. The secondary outcome measures related to the effectiveness of this procedure and included: pre- and post-procedure NRS scores; ODI scores initially, and at post RFN follow-up; analgesic consumption initially, and at one-month RFN follow-up; patient satisfaction with the cooled RFN treatment. A procedure was considered categorically successful if the patient gained ≥50% pain relief and was satisfied with its results. Results81/84 (96.4%; 95% CI [89.9%, 99.3%]) of the diagnostic SLB blocks lead to temporary sensory deficit to pinprick in the MCN distribution. If the block was positive, 58/58 (100.00%; 95% CI [93.8, 100.00%]) of the procedures led to hypoesthesia. For negative diagnostic blocks, 3/26 (11.5%; 95% CI [2.4%, 30.2%]) procedures lead to no hypoesthesia. The buttock hypoesthesia persisted in all patients with successful cooled RFN one month after this intervention. Among the patients with unsuccessful RFN, only 2/9 (22.2%, 95%CI [2.8%, 60.0]) still had hypoesthesia, but the rest of this group had no sensory deficit on pinprick examination. At 6-months follow-up buttock hypoesthesia had no association with the success of the procedure.The patients' average NRS scores decreased from baseline 7.1 (SD 1.7) to 4.3 (SD 3.3) at 1-month follow-up after RFN. Categorical success, based on ≥50% pain relief coupled with patients' satisfaction, was achieved in 12/21 (57.1%; 95% CI [34.0%, 78.2%]) of the subjects. Average ODI percentage score decreased from 41.7% (SD 15.1%) to 31.8% (SD 17.8%) at the primary endpoint of the study. ConclusionMCNs provide regular and clinically detectable innervation to the skin area overlaying posterior-medial aspects of the gluteus maximums muscle. Therefore, any technically accurate diagnostic block, irrespective of whether the patients have positive or negative responses, should result in the development of hypoesthesia in the area supplied by the MCNs. Immediately after the completion of the diagnostic procedure, the adequacy of the block should be tested. Absence of hypoesthesia suggests that the block may have been technically inadequate. Numbness in the buttock area innervated by the MCNs may serve as a marker of an adequately performed RFN procedure. If this procedure is unsuccessful in patients who do not develop post-neurotomy numbness in the area supplied by the MCNs, the failure of the intervention may stem from its inaccurate implementation rather than from its inherent ineffectiveness.

Risk factors for early-onset radiographical adjacent segment disease in patients with spondylolytic spondylolisthesis after single-level posterior lumbar interbody fusion

BACKGROUND CONTEXTThe risk factors for radiographical adjacent segment disease (ASD) in patients with degenerative spondylolisthesis have been previously reported. However, there are only few reports on patients with spondylolytic spondylolisthesis who underwent single-level posterior lumbar interbody fusion (PLIF). PURPOSEThe study aimed to investigate the risk factors for radiographical ASD in patients with L5–S1 spondylolytic spondylolisthesis who underwent single-level PLIF. STUDY DESIGN/SETTINGA retrospective study PATIENT SAMPLEThis study retrospectively reviewed 135 consecutive patients (91 men and 44 women) with symptomatic L5–S1 spondylolytic spondylolisthesis who underwent single-level PLIF. OUTCOME MEASURESThe pre- and postoperative (at the final follow-up) spinopelvic parameters, % slip, sacral slope, lumbar lordosis (LL), pelvic tilt, pelvic incidence (PI), PI minus LL (PI − LL), lumbosacral angle, C7 sagittal vertical axis, and thoracic kyphosis were measured using standing radiographs. METHODSRadiographical ASD was defined as disc height loss (>3 mm), increase of posterior angulation (>5°), or progression of spondylolisthesis (>3 mm) between the pre- and postoperative radiographs. Pfirrmann's classification was used to evaluate disc degeneration. The radiographical parameters and changes between the pre- and postoperative values were evaluated and compared for the non-ASD and ASD groups. Binary logistic regression analysis was performed to evaluate the adjusted associations between each potential explanatory variable and ASD development. RESULTSThe radiographical ASD incidence was 11%. Additionally, 60% of the patients with ASD had radiographical ASD at 1 year and all cases of radiographical ASD in this follow-up period occurred within 3 years after the initial surgery. The mean period of ASD occurrence after initial surgery was 21.7 ± 12.6 months. No patients required reoperation for radiographical ASD. Multivariate analysis revealed that a preoperative (odds ratio [OR], 5.9; 95% confidence interval [CI], 1.2–28.9; p=.03) and a postoperative (OR, 6.5; 95% CI, 1.2–34.5; p=.03) PI − LL of ≥15° were risk factors for radiographical ASD. CONCLUSIONSPre- and postoperative PI − LL value mismatch was identified as significant independent risk factors for radiographical ASD in patients with L5–S1 spondylolytic spondylolisthesis. Obtaining larger lordosis at L5–S1 may be the key to preventing radiographical ASD.

What happens at the L5/S1 facet joint when implants are placed across the sacroiliac joint?

BackgroundInjuries to the posterior pelvic ring are often stabilized with fixation across the sacroiliac joint (SIJ). However, the compensatory changes at the neighboring L5/S1 facet joint are unknown. The objective of this study was to determine the compensatory change in pelvic kinematics and contact forces at the L5/S1 facet joint after fixation across the sacroiliac joint (SIJ) using a cadaveric model. MethodsFive fresh-frozen cadaveric pelvis specimens were dissected to remove non-structural soft tissue. Retroreflective markers were fixed to the L5 body, S1 body and bilateral anterior superior iliac spines to represent the motion of L5, S1 and the ileum, respectively. Pressure sensors were inserted in both L5/S1 facet joints. Testing was performed using a robotic system that applied load to mimic ambulation. Testing was performed prior to SIJ fixation, after unilateral SIJ fixation and bilateral fixation. ResultsContact force at the L5/S1 facet joint significantly increased by 55% from 48.4 N to 75.2 N following unilateral fixation (p = 0.0161) and increased by 100% to 96.9 N after bilateral fixation (p = 0.0038). Unilateral SIJ fixation increased flexion of the ilium relative to L5 from 1.2° to 2.0° (p = 0.01) and increased axial rotation of L5 relative to S1 from 0.7° to 1.6° (p = 0.001). Bilateral fixation increased flexion of the ilium relative to L5 to 2.0° from 1.2° prior to fixation (p = 0.001), increased axial rotation of L5 relative to S1 to 1.2° from 0.7° prior to fixation (p = 0.002) and increased flexion of L5 relative to S1 to 2.4° from 1.5° prior to fixation (p = 0.04). ConclusionThe L5/S1 facet joint experiences compensatory increased motion under increased contact force after unilateral and bilateral SIJ fixation, possibly predisposing it to adjacent segment arthritis. Level of EvidenceV, cadaveric study

Surgical outcomes with anatomic reduction of high-grade spondylolisthesis revisited: an analysis of 101 patients.

The ideal strategy for high-grade L5-S1 isthmic spondylolisthesis (HGS) remains controversial. Critical questions include the impact of reduction on clinical outcomes, rate of pseudarthrosis, and postoperative foot drop. The scope of this study was to delineate predictors of radiographic and clinical outcome factors after surgery for HGS and to identify risk factors of foot drop. This was a single-center analysis of patients who were admitted for HGS, defined as grade III or greater L5 translation according to the Meyerding (MD) classification. Complete postoperative reduction was defined as MD grade I or less and L5 slip < 20%. Forty-six patients completed health-related quality-of-life questionnaires (Oswestry Disability Index, Physical Component Summary of SF-36, and visual analog scale) and ≥ 2 years' follow-up (average 105 months). A 540° approach was used in 61 patients, a 360° approach was used in 40, and L5 corpectomy was used in 17. Radiographic analysis included measures of global spinopelvic balance (e.g., pelvic incidence [PI], lumbar lordosis) and measurement of lumbosacral kyphosis angle (LSA), L4 slope (L4S), L5 slip (%), and postoperative increase of L5-S1 height. The authors included 101 patients with > 1 year of clinical and radiographic follow-up. The mean age was 26 years. Average preoperative MD grade was 3.8 and average L5 slip was 81%; complete reduction was achieved in 55 and 42 patients, respectively, according to these criteria. At follow-up, LSA correlated with all clinical outcomes (r ≥ 0.4, p < 0.05). Forty patients experienced a major complication. Risk was increased in patients with greater preoperative deformity (i.e., LSA) (p = 0.04) and those who underwent L5 corpectomy (p < 0.01) and correlated with greater deformity correction. Thirty-one patients needed revision surgery, including 17 for pseudarthrosis. Patients who needed revision surgery had greater preoperative deformity (i.e., MD grade and L5 slip) (p < 0.01), greater PI (p = 0.02), and greater postoperative L4S (p < 0.01) and were older (p = 0.02), and these patients more often underwent L5 corpectomy (p < 0.01). Complete reduction was associated with lower likelihood of pseudarthrosis (p = 0.08) and resulted in better lumbar lordosis correction (p = 0.03). Thirty patients had foot drop, and these patients had greater MD grade and L5 slip (p < 0.01) and greater preoperative LSA (p < 0.01). These patients with foot drop more often required L5 corpectomy (p < 0.01). Change in preoperative L4S (p = 0.02), LSA (p < 0.01), and L5-S1 height (p = 0.02) were significantly different between patients with foot drop and those without foot drop. A significant risk model was established that included L4S change and PI as independent variables and foot drop as a dependent variable (82% negative predictive value and 71% positive predictive value, p < 0.01). Multivariable analysis identified factors associated with foot drop, major complications, and need for revision surgery, including degree of deformity (MD grade and L5 slip) and correction of LSA. Functional outcome correlated with LSA correction.

Association between severe lumbar disc degeneration and self-reported occupational physical loading.

ObjectivesOccupational physical loading has been reported to be associated with intervertebral disc degeneration. However, previous literature reports inconsistent results for different vertebral levels. The aim of our study was to investigate the association between lumbar disc degeneration (LDD) at different vertebral levels and the self‐reported physical loading of occupation.MethodsThe study population consisted of 1,022 postmenopausal women and was based on the prospective Kuopio Osteoporosis Risk Factor and Prevention (OSTPRE) study cohort. The severity of LDD was graded from T2‐weighted MRI images using the five‐grade Pfirrmann classification. Five intervertebral levels (L1–L2 to L5–S1) were studied (total 5110 discs). The self‐rated occupational physical loading contained four groups: sedentary, light, moderate, and heavy.ResultsThe heavy occupational physical loading group had higher odds for severe LDD at the L5–S1 vertebral level (OR 1.86, 95% CI: 1.19–2.92, p = .006) in comparison with the sedentary work group. A clear trend of increasing disc degeneration with heavier occupational loading was also observed at the L5–S1 level. Age, smoking, and higher body mass index (BMI) were associated with more severe LDD. Leisure‐time physical activity at the age of 11–17 years was associated with less severe LDD. Controlling for confounding factors did not alter the results.ConclusionsThere appears to be an association between occupational physical loading and severe disc degeneration at the lower lumbar spine in postmenopausal women. Individuals in occupations with heavy physical loading may have an increased risk for work‐related disability due to more severe disc degeneration.

Localization of L5–S1 Disc Space by Utilizing Simple on Table Surface Marking in Posterior Lumbar Spine Surgery without Any Radiological Assistance

Background: Localization of the spinal levels is an important task during any spinal surgery. The purpose of the study is to assess the accuracy and reliability in identifying L5–S1 disc space by surface localization using Venus of dimple as a landmark in posterior spinal surgery without undertaking any radiological assistance. Methodology: We prospectively analyzed 39 patients, who had undergone primary posterior spine surgery, especially for Prolapsed intervertebral disc mostly affecting the lumbosacral region. Following surface marking using Venus of dimple as a landmark, patients were subjected to surgery with or without prior X-ray evaluation solely on surface localization of L5–S1 disc space. Intraoperatively, the accuracy and reliability of the surface marking were determined. Results: Sixty-four percent of the patients had accurate L5–S1 spine level localization utilizing the above clinical palpatory methods, while 23% of the cases identified L5 spine intraoperatively. On analyzing this surface topographical method with that of X-ray in standing position, the sensitivity and specificity came to be 93.3% and 49%, respectively, with a positive predictive value of 77.8%. Conclusion: The method of localization of L5–S1 space described although cannot fully replace the role of fluoroscopic assistance during spinal surgery, still it is an important, simple, and reliable alternative method of localization which demands its application by the spine surgeons, especially in the beginning of their carrier and in certain specific situations.

Foraminal Stenosis at L5-S1 as an Overlooked Pathology of Bilateral Radiculopathy: A Case Series.

The classical symptom of foraminal stenosis is unilateral radiculopathy. Bilateral radiculopathy caused purely by foraminal stenosis is rare. Here, we report five cases of bilateral L5 radiculopathy caused purely by L5-S1 foraminal stenosis and describe the clinical and radiological features of these patients in detail. Among the five patients, two were men and three were women with an average age of 69 years. Four patients had undergone surgeries at L4-5 level, previously. All the patients showed an improvement in symptoms in the post-operative period. After a certain period, the patients complained of bilateral leg pain and numbness. An additional surgery was performed in two patients; however, there was no improvement in symptoms. One patient, who did not undergo surgery, was treated conservatively for 3 years. All the patients had been suffering from bilateral leg symptoms before their first visit to our hospital. The neurological findings in these patients were consistent with bilateral L5 radiculopathy. The average pre-operative Japanese Orthopedic Association (JOA) score was 13 out of 29 points. Bilateral foraminal stenosis at L5-S1 level was confirmed using a three-dimensional magnetic resonance imaging or computed tomography. Posterior lumbar interbody fusion was performed in one patient and bilateral lateral fenestration using Wiltse's approach was performed in four patients. The neurological symptoms recovered immediately after surgery. The average JOA score at 2-year follow-up was 25 points. Spine surgeons may overlook the pathology of foraminal stenosis, particularly in patients with bilateral radiculopathy. Familiarity with the clinical and radiological features of symptomatic lumbar foraminal stenosis is necessary to properly diagnose bilateral foraminal stenosis at L5-S1 level.