Lordosis loss in degenerative spinal conditions.

PURPOSE: To establish whether common degenerative lumbar spine conditions have a predictable sagittal profile and associated range of lordosis. The spinopelvic balance of a normal population and normal ranges are well described in the literature. There is also evidence that certain degenerative conditions can lead to a preponderance of loss of lordosis at specific spinal levels. There is limited literature on the range and magnitude of loss of lordosis for known degenerative lumbar spine pathologies. METHODS: A retrospective analysis of prospectively obtained radiographs from a dual surgeon database was performed and imaging analysed for spinopelvic parameters. Degenerative conditions studied were; Lumbar degenerative spondylolisthesis (L3/4 and L4/5 analysed separately), L5/S1 degenerative disc disease, L5/S1 isthmic spondylolisthesis. Pelvic incidence, sacral slope, pelvic tilt, segmental and global lumbar lordosis, vertebral lordosis and lumbar vertical axis were measured. RESULTS: The range of change in segmental lordosis was normally distributed for all studied degenerative spinal conditions except L5/S1 isthmic spondylolisthesis. L5/S1 degenerative disc disease affected younger adults (mean age 37), whilst degenerative spondylolisthesis at L3/4 and L4/5 affected older adults (mean ages 69.5 and 68.9 respectively). Removing an outlying high-grade L5/S1 isthmic spondylolisthesis made the data distribution approach a normal distribution. CONCLUSION: Most degenerative spinal pathologies cause a normally distributed spectrum of deformity which should be addressed and corrected with a tailored, individualised surgical plan for each patient. Universal treatment recommendations should be interpreted with caution.

Computed tomography analysis of sacropelvic parameters in relation to anterior access to the lumbosacral disc.

Purpose: Anecdotally a higher pelvic incidence (PI) confers a 'deeper' pelvis with the potential for challenging access, yet this is ill-defined in the existing literature. The aim of this study was to assess the relationship of sacropelvic sagittal parameters and their relationship with the projection angle (PA), an indicator of access to and orientation of the lumbosacral disc with respect to the pelvis and identify a threshold PI value beyond which more difficult surgical access may be anticipated.Materials and methods: Computed tomography (CT) scans taken for trauma were studied. Measures including the PI, sacral kyphosis (SK), sacral table angle (STA), PA and anterior pelvic angle (APA) were taken. The PA is the angle subtended by a line from the apex of the pubic symphysis to the sacral promontory and a line running along the sacral endplate. A positive value is obtained when the line from the endplate runs superior to the symphysis.Results: 168 scans were reviewed, mean age 44.2 years (s.d. 18.4). The mean PI was 50.0 (s.d. 10.2), SK 24.4 (s.d. 12.3), and STA 102.0 (s.d. 6.1). The mean PA was 20.1 (range -14 to 46; s.d. 10.3). PA correlated with PI (R = -0.892; p < .001) and also SK (R = -0.760; p < .001). With PI values above 73 the PA is likely to be negative with the lumbosacral disc orientation falling behind the pubic symphysis. One-way analysis of variance showed differences in PA according the six subclasses of PI.Conclusion: The PA, as an indicator of the orientation of the lumbosacral disc with respect to the pelvis, correlated strongly with the PI. Patients with high PI are more likely to have a lumbosacral disc with trajectory falling behind the pubic symphysis and surgeons should closely analyse pelvic anatomy, particularly in patients with high PI.

Pelvic Incidence: Computed Tomography Study Evaluating Correlation with Sagittal Sacropelvic Parameters.

Normal values for spinal alignment are often based on the pelvic incidence (PI), defined as the angle subtended by a line from the bicoxofemoral axis to the midpoint of the sacral endplate and a line perpendicular to the midpoint. Despite widespread use, determinants of its values remain obscure. The aim of this study was to determine correlation of sacropelvic parameters with the PI on computed tomography (CT). CT scans performed for trauma were identified over a 1-year period. Patients aged over 16 were included. PI, sacral anatomic orientation, sacral table angle (STA), sacral kyphosis (SK), pelvic thickness (PTH), femorosacral pelvic angle, pelvisacral angle, and sacropelvic angle were measured. Additional novel measures including crest-to-pubis distance, crest-to-sacrum distance (CSD), inlet distance, outlet distance, and inlet-outlet angle were taken. One hundred and seventy-seven scans were analyzed. Mean age 44.3 years; 62% male. The mean PI was 50.1 (SD 10.8; range 29-87). SK (r = 0.769), inlet-outlet angle (r = -0.533), PTH (r = -0.370), CSD (r = 0.290), and STA (r = -0.276) significantly correlated with PI. Multivariate analysis developed a predictive equation of: PI = 101.45 - (0.52 × STA) + (0.67 × SK) - (0.34 × inlet-outlet angle), with an adjusted R2 0.734 (P < 0.001). Measures that represent the sacral morphology, particularly SK, and the position of the sacrum in space correlated strongly with the PI and contributed strongly to a predictive equation. These findings may direct further efforts to explore how the PI is determined and therefore how it may be modified. Clin. Anat. 33:237-244, 2020. © 2019 Wiley Periodicals, Inc.

Improved biomechanics of two alternative kyphoplasty cementation methods limit vertebral recollapse.

The clinical efficacy of vertebral cement augmentation for compression fractures (VCFs) remains undetermined. Recent studies have shown that refracture and progression of deformity may occur after augmentation with significant clinical consequences. Vertebral body height loss following kyphoplasty has also been observed with cyclic loading. We hypothesized that height loss is partly due to lack of cement fill past the margin of cancellous bone created by balloon expansion with subsequent failure under load. The biomechanical characteristics of two alternative cementation techniques were compared to standard kyphoplasty in cyclically loaded cadaveric VCF constructs. Sectioned osteoporotic thoracolumbar cadaveric spines were compressed to 75% of anterior vertebral height. Specimens were then allocated to standard kyphoplasty, balloon pressurization (BP), with reinflation of the balloon after 50% cement injection, or endplate post (EP), with perforation of the cavity rim using an articulating curette prior to injection. Following cementation, each specimen was preconditioned and loaded over 100,000 cycles. All techniques improved vertebral height (p's < 0.005). The EP and BP techniques provided greater cement fill than the standard technique (p's ≤ 0.01). Normalized vertebral height loss following 100,000 cycles was reduced with the EP technique versus standard kyphoplasty (p < 0.04). Height loss was inversely correlated with cement fill (p < 0.03). No vertebral recollapse occurred with the EP technique in blinded radiographic analysis. Statement of clinical significance: The EP technique demonstrated improved biomechanical characteristics versus the standard technique in cadaveric osteoporotic VCF constructs with decreased recollapse following cementation. This technique may have increased efficacy in cases when kyphoplasty more substantially improves vertebral body height. © 2018 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 36:3225-3230, 2018.

Do position and size matter? An analysis of cage and placement variables for optimum lordosis in PLIF reconstruction.

PURPOSE: To examine monosegmental lordosis after posterior lumbar interbody fusion (PLIF) surgery and relate lordosis to cage size, shape, and placement. METHODS: Eighty-three consecutive patients underwent single-level PLIF with paired identical lordotic cages involving a wide decompression and bilateral facetectomies. Cage parameters relating to size (height, lordosis, and length) and placement (expressed as a ratio relative to the length of the inferior vertebral endplate) were recorded. Centre point ratio (CPR) was the distance to the centre of both cages and indicated mean position of both cages. Posterior gap ratio (PGR) was the distance to the most posterior cage and indicated position and cage length indirectly. Relationships between lordosis and cage parameters were explored. RESULTS: Mean lordosis increased by 5.98° (SD 6.86°). The cages used varied in length from 20 to 27 mm, in lordosis from 10° to 18°, and in anterior cage height from 10 to 17 mm. The mean cage placement as determined by CPR was 0.54 and by PGR was 0.16. The significant correlations were: both CPR and PGR with lordosis gain at surgery (r = 0.597 and 0.537, respectively, p < 0.001 both), cage lordosis with the final lordosis (r = 0.234, p < 0.05), and anterior cage height was negatively correlated with a change in lordosis (r = -0.297, p < 0.01). CONCLUSION: Cage size, shape, and position, in addition to surgical technique, determine lordosis during PLIF surgery. Anterior placement with sufficient "clear space" behind the cages is recommended. In addition, cages should be of moderate height and length, so that they act as an effective pivot for lordosis.

Universal No-fault Compensation is Associated With Improved Return to Work Rates in Spine Fusion.

STUDY DESIGN: Retrospective cohort study and systematic literature review. OBJECTIVE: To examine the influence of "universal no-fault compensation" upon return-to-work rates in patients undergoing lumbar spinal fusion, and then to make comparison with workers' compensation (WC) and non-workers' compensation (non-WC) claimants. SUMMARY OF BACKGROUND DATA: Compensation has an adverse influence upon outcomes and return to work in lumbar spinal fusion. It is unclear whether this is due to the compensation per se, or due to the features of WC including its adversarial environment, delayed resolution of claims, and need for disability enhancement to promote compensation. The New Zealand Accident Compensation Corporation (ACC) is a universal no-fault system offering early treatment and salary reimbursement. Given the differing features of these compensation systems, comparison of return-to-work rates may give insight into the differing outcomes for the two compensation systems. METHODS: From a cohort of 428 patients undergoing lumbar spinal fusion, 178 patients covered by ACC system underwent a structured interview to determine pre-injury, pre-surgical, and post-surgical work status. A systematic literature review was performed relating to lumbar spine fusion, return to work, and WC. RESULTS: The return-to-work rate for the ACC patients in work at the time of their injury was 81%. The systematic review of 21 studies including 2519 subjects revealed a return-to-work rate of 40% for WC patients, and 74% for non-WC patients (P < 0.001). There was a significantly greater return-to-work rate for ACC patients than WC patients (P < 0.001), but no difference between ACC and non-WC patients. CONCLUSION: The return-to-work rates for a universal no-fault compensation system are higher than those under WC cover, and are compatible with non-WC cases. This suggests that the features of WC may contribute to the inferior return-to-work rates.

2009 ISSLS Prize Winner: Does discography cause accelerated progression of degeneration changes in the lumbar disc: a ten-year matched cohort study.

STUDY DESIGN: Prospective, match-cohort study of disc degeneration progression over 10 years with and without baseline discography. Objectives. To compare progression of common degenerative findings between lumbar discs injected 10 years earlier with those same disc levels in matched subjects not exposed to discography. Summary of Background Data. Experimental disc puncture in animal and in vivo studies have demonstrated accelerated disc degeneration. Whether intradiscal diagnostic or treatment procedures used in clinical practice causes any damage to the punctured discs over time is currently unknown. METHODS: Seventy-five subjects without serious low back pain illness underwent a protocol MRI and an L3/4, L4/5, and L5/S1 discography examination in 1997. A matched group was enrolled at the same time and underwent the same protocol MRI examination. Subjects were followed for 10 years. At 7 to 10 years after baseline assessment, eligible discography and controlled subjects underwent another protocol MRI examination. MRI graders, blind to group designation, scored both groups for qualitative findings (Pfirrmann grade, herniations, endplate changes, and high intensity zone). Loss of disc height and loss of disc signal were measured by quantitative methods. RESULTS: Well matched cohorts, including 50 discography subjects and 52 control subjects, were contacted and met eligibility criteria for follow-up evaluation. In all graded or measured parameters, discs that had been exposed to puncture and injection had greater progression of degenerative findings compared to control (noninjected) discs: progression of disc degeneration, 54 discs (35%) in the discography group compared to 21 (14%) in the control group (P = 0.03); 55 new disc herniations in the discography group compared to 22 in the control group (P = 0.0003). New disc herniations were disproportionately found on the side of the anular puncture (P = 0.0006). The quantitative measures of disc height and disc signal also showed significantly greater loss of disc height (P = 0.05) and signal intensity (P = 0.001) in the discography disc compared to the control disc. CONCLUSION: Modern discography techniques using small gauge needle and limited pressurization resulted in accelerated disc degeneration, disc herniation, loss of disc height and signal and the development of reactive endplate changes compared to match-controls. Careful consideration of risk and benefit should be used in recommending procedures involving disc injection.

Anatomic determination of optimal entry point and direction for C1 lateral mass screw placement.

STUDY DESIGN: Anatomic study of C1 osteology using computerized tomography. OBJECTIVES: To define the anatomy of the C1 lateral mass and make recommendations for optimal entry point and screw placement at C1. SUMMARY OF BACKGROUND DATA: C1 lateral mass screw fixation is a reliable biomechanical technique that gives equivalent stability to that of Magerl transarticular screw fixation combined with posterior wiring for C1-C2 fusion. Use of a lateral mass screw allows alternative stabilization constructs to the transarticular technique when C2 vertebral artery anatomy is unfavorable. Because the vertebral artery travels lateral to the lateral mass, then crosses medially over the C1 neural arch, it is at risk during instrumentation. Medially, the cord and canal contents are at risk. While the anatomy of the C1 vertebra and lateral mass is well known, specific definition of ideal entry points, screw pathway direction, and dimensions of screws requires further clarification to enable a clinically safe surgical technique. METHODS: Fifty consecutive patients underwent computerized tomography scans of their cervical spine. Using calibrated scans, measurements were taken to give the average dimensions of the C1 vertebra with a view for insertion of lateral mass screws beneath the posterior arch. The range of anatomic dimensions was examined to assess risk of vertebral artery damage in this population. RESULTS: The average length of screw within the lateral mass is 17.9 mm with 21.5 mm of screw posterior to the lateral mass, necessary to allow rod placement posteriorly. The safest entry point was directly beneath the medial edge of the posterior arch/lamina where it joins the lateral mass. The ideal direction of screw angulation in the sagittal plane was parallel to the posterior arch of C1. In the medial lateral plane, direct anterior placement could be used, but the lateral mass will tolerate 20 degrees of medial angulation from this starting point. The average distance between the vertebral artery foramen laterally and the screw pathway was 8.8 mm using these landmarks, and 5.8 mm from the medial aspect of the lateral mass. The range of anatomic variation was such that 9 lateral masses had a vertebral artery foramen to screw distance of only 3 mm. The vertebral artery was not at risk when these anatomic landmarks were used. CONCLUSIONS: C1 lateral mass screws are best placed beneath the posterior arch, parallel with the arch in the sagittal plan. The entry point is the medial border of the neural arch at its junction with the lateral mass. Straight ahead screw direction is safe in the axial plane, but up to 20 degrees of medial angulation will increase the safety margin from the vertebral artery foramen, and this technique avoids vertebral artery damage and optimizes lateral mass screw purchase. We suggest that this is the preferred method of entry into the lateral mass of C1.

Is the self-reported history accurate in patients with persistent axial pain after a motor vehicle accident?

BACKGROUND CONTEXT: A patient's self-reported history has, in general, assumed to be accurate. Clinical management of individuals with persistent axial pain after a motor vehicle accident (MVA) and measures to prevent future MVA, spinal cord injury, and traffic deaths often depend on a presumed accurate report of preexisting axial pain, drug, alcohol, and psychological problems to initiate intervention. In addition, research efforts to determine the effects of MVA on subsequent health are often predicated on a presumed accurate history from the patient of past medical and psychosocial problems. Despite so many clinical, public health, and research efforts being dependent on an accurate assessment of pre-injury health, the validity of the self-reported history after MVA has not been systematically investigated. PURPOSE: To determine the validity of self-reported history in subjects with axial neck or back pain attributed to a recent MVA. STUDY DESIGN: A prospective, multiclinic validation study examining the critical elements of a patient's self-reported history after an MVA judged against an audit of his or her medical records. PATIENT SAMPLE: A cohort of consecutive patients with persistent axial pain after an MVA was prospectively identified from five spine-specialist's outpatient clinics. Of 702 patients, 335 subjects were randomly selected for auditing of their medical records. OUTCOME MEASURES: Self-reported demographic and clinical features were recorded by standardized questionnaires and clinical interviews. Audits compared these responses to an extensive medical record search. METHODS: The self-reported prevalence of preexisting axial pain, at-risk comorbidities (psychological distress, alcohol, and drug abuse), and control conditions (hypertension and diabetes) was recorded. The medical records of a random sample of 50% of the enrolled cohort underwent auditing of their medical records in a wide search of network paper and electronic and archived records, and compared with the self-reported history of pre-accident health. RESULTS: Overall, approximately 50% of the subjects were found to have previous axial pain problems at audit when none was reported to the spine-specialist after an MVA. Similarly, approximately 75% of the subjects were found to have one or more preexisting comorbid conditions at audit that were not reported during the evaluation after the MVA (alcohol abuse, illicit drug use, and psychological diagnosis). For those who perceived that the accident was the fault of another, as opposed to their own or no one's fault, the documented previous back and neck pain troubles in the medical records was more than twice the self-reported rate of these problems (p<.01). The rate of previously documented psychological problems was more than seven times that of the self-reported rate (p = 0.001). In those subjects who perceived that the accident was their own or no one's fault, a lesser degree of under-reporting of axial pain and comorbid conditions was found. CONCLUSION: The validity of the patient's self-reported history when presenting with persistent axial pain after an MVA appears poor in this large multiclinic random sample.The self-reported rates of alcohol abuse, illicit drug use, and psychological diagnosis, as well as prior axial pain were significantly lower than that seen in the medical records, especially in thosewho perceive that the MVA was another's fault. The failure to recognize this under-reporting may seriously compromise clinical care, public health efforts at injury prevention, and research protocols dependent on accurate pre-accident morbidity assessments.

Selection of fusion levels in adolescent idiopathic scoliosis using fulcrum bending prediction: a prospective study.

STUDY DESIGN: A prospective study of 50 consecutive patients undergoing selective thoracic fusion for idiopathic scoliosis with minimum 2 year follow-up. OBJECTIVE: We aim to establish the validity and safety of a new strategy using fulcrum bending (FB) radiographs and the inherent flexibility of the curve to select fusion levels for King type 2 and 3 curves (Lenke 1a, 1b, and 1c). The purpose of this new strategy is to preserve motion segments compared to the traditional method of selecting fusion levels. SUMMARY OF BACKGROUND DATA: The aim of fusion in idiopathic scoliosis is to achieve a balanced spine with the shortest fusion preserving motion segments particularly in the lumbar spine. Conventional strategies for choosing fusion levels have been based on the standing radiographs and have not taken into account the flexibility of the curve. METHODS: We followed 50 consecutive patients who underwent selective thoracic fusion for King 2 and 3 curves (Lenke 1a, 1b, and 1c). The fusion levels were chosen based on our new strategy using the FB radiograph. Twenty-five patients were fused using a hook system and 25 with a hybrid system of hooks and screws. All patients were observed until skeletal maturity and a minimum of 2 years. The curve correction, trunk shift, radiographic shoulder height, list were recorded at the preoperative stage, postoperative stage, and final follow-up. RESULTS: The patients had an average age of 15.4 years. The average preoperative Cobb angle was 55.4 degrees and final follow-up Cobb angle for the primary curve was 24.1 degrees, with no difference between the 2 groups. With the new strategy, we were able to save levels in 31 patients (62%), compared to the conventional method of selecting the lowest instrumented vertebra. There was a statistically significant difference in the correction of the fusion mass Cobb angle between the hook and hybrid groups. There was significant improvement in the trunk shift after surgery. Ninety-six percent of patients had balanced or minimally imbalanced shoulders at final follow-up. Three patients had tilting of the vertebra below the fusion mass into the primary curve that did not progress at skeletal maturity. CONCLUSION: The new objective strategy for determining fusion levels using FB radiographs is safe and effective. With considering the flexibility of the curve, we are able to save levels distally in over 60% of patients. This strategy takes into account the power of modern instrumentation.

Facet joint orientation in spondylolysis and isthmic spondylolisthesis.

STUDY DESIGN: The orientation of facet joints (FJs) in a normal population and isthmic spondylolisthesis (IS) population was assessed using magnetic resonance imaging in the lumbar spine. OBJECTIVE: To document the difference in FJ orientation (FJO) between a normal population and a population with spondylolysis of L5 and IS. SUMMARY OF BACKGROUND [corrected] DATA: Spondylolysis and IS have both a familial and mechanical etiology, yet the phenotypic expression of the familial etiology is unknown except for the observation of spinal bifida occulta. Other posterior element abnormalities are unrecognized, and any FJO abnormality below the pars defect has been ignored because of presumed previous mechanical defunctioning by the development of that pars defect at an earlier age. The recognition of multilevel sagittal FJO in L4/5 degenerative spondylolisthesis (DS), raises the possibility that more proximal segment examination may reveal FJ variations in IS. METHODS: Magnetic resonance imaging scans were used to measure the orientation of the FJ at L3/4, L4/5, and L5/S1 in 30 individuals with normal scans, and 30 patients with IS. The angular measurement recorded was in relation to the coronal plane. Repeated measurements confirmed the validity of the method. RESULTS: Mean measurement of axial FJO at L3/4 and L4/5 was 51.1 and 42.5 degrees in the controls, and 45.2 and 35.0 degrees in IS. The more coronal angulation at the levels above a pars defect in IS was highly statistically significant (P = <0.001 at L3/4 and P = <0.0001 at L4/5). At L5/S1, orientations were the same (39 degrees) in each group. CONCLUSIONS: Relative coronal FJO in the lumbar spine may be the phenotypic expression of the familial etiology of IS. This may result in increased stress concentration in the pars between or below coronally oriented FJs. These more coronal FJOs in IS may also explain the common observation of retrolisthesis at L4/5 above IS when the L4/5 disc degenerates, lateral overhang of the L4/5 FJ to the L5 pedicle entry point above an IS, and the rare combination of DS at L4/5 and IS at L5/S1 when both disorders are separately common. This latter observation can be explained by the observation that DS occurs in those individual with sagittal lumbar facets, and that IS occurs in those with more coronal FJs.

A brief overview of evidence-informed management of chronic low back pain with surgery.

The management of chronic low back pain (CLBP) has proven to be very challenging in North America, as evidenced by its mounting socioeconomic burden. Choosing among available nonsurgical therapies can be overwhelming for many stakeholders, including patients, health providers, policy makers, and third-party payers. Although all parties share a common goal and wish to use limited health-care resources to support interventions most likely to result in clinically meaningful improvements, there is often uncertainty about the most appropriate intervention for a particular patient. To help understand and evaluate the various commonly used nonsurgical approaches to CLBP, the North American Spine Society has sponsored this special focus issue of The Spine Journal, titled Evidence-informed management of chronic low back pain without surgery. Articles in this special focus issue were contributed by leading spine practitioners and researchers, who were invited to summarize the best available evidence for a particular intervention and encouraged to make this information accessible to nonexperts. Although this special focus issue was focused on nonoperative care, it was deemed important to provide an overview of the surgical management of CLBP. This is intended to inform stakeholders of surgical options that are available to them should nonsurgical interventions prove ineffective or contraindicated. It is hoped that articles in this special focus issue will be informative and aid in decision making for the many stakeholders evaluating nonsurgical interventions for CLBP.

Painful lumbosacral melorheostosis treated by fusion.

STUDY DESIGN: A case report of low back pain associated with a diagnosis of melorheostosis of the lumbosacral spine. OBJECTIVE: To describe a rare presentation of melorheostosis and subsequent successful surgical treatment. SUMMARY OF BACKGROUND DATA: Melorheostosis is a rare condition and spinal pain has not been described in association with the condition. METHODS: A patient with disabling low back pain and suspected melorheostosis of the lumbosacral spine responded favorably to diagnostic facet joint blocks. Treatment was lumbosacral fusion and biopsy of the abnormal bone. The densely sclerotic bone presented technical difficulties requiring modification of surgical technique. RESULTS: Dramatic pain and disability reduction occurred following lumbosacral fusion. Histologic examination was consistent with melorheostosis. CONCLUSION: Melorheostosis rarely causes severe low back pain that can respond favorably to fusion surgery.