Cervical spondylotic myelopathy.

Cervical spondylotic myelopathy (CSM) is a progressive degenerative condition of the cervical spine and the most common cause of spinal cord injury in adults >55 years of age. Degenerative changes in the spine lead to spinal cord compression, resulting in symptoms such as gait instability, loss of dexterity in the hands, weakness, and sensory deficits. Diagnosis is delayed by 2,2-6,3 years and includes clinical examination and imaging such as MRI. Management of CSM is primarily surgical treatment. This review highligths the importance of early recognition and appropriate treatment in optimising patient outcomes.

Glial fibrillary acidic protein is a robust biomarker in cerebrospinal fluid and peripheral blood after traumatic spinal cord injury: a prospective pilot study.

PURPOSE: Biochemical biomarkers to determine the injury severity and the potential for functional recovery of traumatic spinal cord injury (TSCI) are highly warranted; however, it remains to be clarified whether cerebrospinal fluid (CSF) or peripheral blood (PB) is the ideal sample media. This study aims to measure and compare biomarker concentrations in CSF and PB and to explore associations between biomarker concentrations and injury severity, i.e., American Spinal Injury Association (ASIA) Impairment Scale (AIS) grade, and biomarker concentrations and clinical outcome, i.e., AIS grade improvement and Spinal Cord Independent Measure version III (SCIM-III) score. METHODS: From 2018 to 2020, we conducted a single-center prospective pilot study of TSCI patients (n=15) and healthy controls (n=15). Sample collection and clinical outcome assessment were performed at median 13 h [IQR: 19], 9 days [IQR: 2], and 148 days [IQR: 49] after TSCI. Concentrations of neuron-specific enolase (NSE); glial fibrillary acid protein (GFAP); neurofilament light chain (NfL); interferon-γ (IFN-γ); interleukin (IL)-1ß, IL-2, IL-4, IL-6, IL-8, IL-10, IL-12p70, and IL-13; and tumor necrosis factor α (TNF-α) were measured and associated to clinical outcomes. RESULTS: The biomarker concentrations were higher in CSF than PB. CSF concentrations of GFAP, NSE, IFN-y, TNF-a, IL-2, IL-12p70, IL-4, IL-10, and IL-13 and PB concentrations of GFAP and IFN-y were significantly associated with AIS grade, but not with AIS grade improvement or SCIM-III score. CONCLUSIONS: Our results support GFAP as a potential diagnostic biomarker that may be measured in CSF as well as PB.

Evaluation of cefuroxime concentration in the intrathecal and extrathecal compartments of the lumbar spine-an experimental study in pigs.

BACKGROUND AND PURPOSE: Optimal antibiotic prophylaxis is crucial to prevent postoperative infection in spinal surgery. Sufficient time above the minimal inhibitory concentration (fT > MIC) for relevant bacteria in target tissues is required for cefuroxime. We assessed cefuroxime concentrations and fT > MIC of 4 µg·ml-1 for Staphylococcus aureus in the intrathecal (spinal cord and cerebrospinal fluid, CSF) and extrathecal (epidural space) compartments of the lumbar spine. EXPERIMENTAL APPROACH: Eight female pigs were anaesthetized and laminectomized at L3-L4. Microdialysis catheters were placed for sampling in the spinal cord, CSF, and epidural space. A single dose of 1500 mg cefuroxime was administered intravenously over 10 min. Microdialysates and plasma were obtained continuously during 8 h. Cefuroxime concentrations were determined by ultra-high-performance liquid chromatography. KEY RESULTS: Mean fT > MIC (4 µg·ml-1 ) was 58 min in the spinal cord, 0 min in the CSF, 115 min in the epidural space, and 123 min in plasma. Tissue penetration was 32% in the spinal cord, 7% in the CSF, and 63% in the epidural space. CONCLUSION AND IMPLICATIONS: fT > MIC (4 µg·ml-1 ) and tissue penetration for cefuroxime were lower in the intrathecal compartments (spinal cord and CSF) than in the extrathecal compartment (epidural space) and plasma, suggesting a significant effect of the blood-brain barrier. In terms of fT > MIC, a single dose of 1500 mg cefuroxime seems inadequate to prevent intrathecal infections related to spinal surgery for bacteria presenting with a MIC target of 4 µg· ml-1 or above.

Subtherapeutic levels of cefuroxime inside a cannulated pedicle screw used in spine surgery: results from a porcine microdialysis study.

BACKGROUND AND PURPOSE: Minimally invasive spine surgery has continuously evolved for specific surgical procedures and patient populations to lower morbidity and the risk of postoperative bacterial infection. Perioperative antibiotic prophylaxis is an important preventive measure and local tissue concentrations can be quantified with microdialysis. Insertion of spinal implants induces tissue trauma and inflammation, which may affect antibiotic proximate implant concentrations. We compared perioperative cefuroxime concentrations inside a cannulated pedicle screw used in minimally invasive spine surgery with the opposite non-instrumented vertebral pedicle. MATERIALS AND METHODS: Microdialysis catheters were placed inside a cannulated pedicle screw and in the opposite non-instrumented vertebral pedicle of the same vertebra (L1) in 8 female pigs through a posterior lumbar surgical approach. Following a single-dose intravenous cefuroxime administration (1.5 g), dialysates and plasma were dynamically sampled over 8 hours. The primary endpoint was time above the cefuroxime clinical breakpoint minimal inhibitory concentration for Staphylococcus aureus of 4 µg/mL (T>MIC4). RESULTS: Median T>MIC4 was 0 h (range 0-0) inside the cannulated pedicle screw, 1.6 h (range 1.1-2.4) in non-instrumented vertebral pedicle, and 1.9 h (range 1.9-2.9) in plasma. CONCLUSION: A single-dose intravenous cefuroxime administration provided low and subtherapeutic concentrations for prevention of infection inside a cannulated pedicle screw in the lumbar spine. Therapeutic concentrations were achieved in the opposite non-instrumented vertebral pedicle up to 1.5-2 h. Therefore, additional prophylactic strategies may be considered in cannulated instrumented spine surgery, especially in high-risk patients. Alternative dosing regimens seem relevant in lumbar spine surgery lasting longer than 1.5 h.

The inflammatory response and blood-spinal cord barrier integrity in traumatic spinal cord injury: a prospective pilot study.

PURPOSE: Triggering of inflammatory responses and disruption of blood-spinal cord barrier (BSCB) integrity are considered pivotal events in the pathophysiology of traumatic spinal cord injury (TSCI). Yet, these events are poorly understood and described in humans. This study aims to describe inflammatory responses and BSCB integrity in human TSCI. METHODS: Fifteen TSCI patients and fifteen non-TSCI patients were prospectively recruited from Aarhus University Hospital, Denmark. Peripheral blood (PB) and cerebrospinal fluid (CSF) were collected at median day 0 [IQR: 1], median day 9 [IQR: 2], and median day 148 [IQR: 49] after injury. PB and CSF were analyzed for immune cells by flow cytometry, cytokines by multiplex immunoassay, and BSCB integrity by IgG Index. RESULTS: Eleven TSCI patients completed follow-up. Results showed alterations in innate and adaptive immune cell counts over time. TSCI patients had significantly increased cytokine concentrations in CSF at the first and second follow-up, while only concentrations of interleukin (IL)-4, IL-8, and tumor necrosis factor-α remained significantly increased at the third follow-up. In PB, TSCI patients had significantly increased IL-6, IL-8, and IL-10 concentrations and significantly decreased interferon-γ concentrations at the first follow-up. Results further showed increased IgG Index indicative of BSCB disruption in seven TSCI patients at the first follow-up, five TSCI patients at the second follow-up, and two patients at the third follow-up. CONCLUSIONS: Our results suggest that TSCI mainly triggers innate inflammatory responses that resolves over time, although with some degree of non-resolving inflammation, particularly in CSF. Our results cannot confirm BSCB disruption in all TSCI patients.

Cerebrospinal fluid and peripheral blood proteomics in Traumatic Spinal Cord Injury: A prospective pilot study.

•Proteomics enable profiling of inflammatory responses after spinal cord injury.•Proteins are differentially expressed over time.•Proteins are differentially expressed in cerebrospinal fluid and peripheral blood.•A poor relationship exists between protein expression and neurological outcome.

Cefuroxime concentrations in the anterior and posterior column of the lumbar spine - an experimental porcine study.

BACKGROUND CONTEXT: Surgical site infection following spine surgery is associated with increased morbidity and mortality. Perioperative antibiotic prophylaxis is a key factor in lowering the risk of acquiring an infection. Previous studies have assessed perioperative cefuroxime concentrations in the anterior column of the cervical spine with an anterior surgical approach. However, the majority of surgeries are performed in the posterior column and many surgeries involve the lumbar spine. PURPOSE: The objective of this study was to compare the perioperative tissue concentrations of cefuroxime in the anterior and posterior column during lumbar spine surgery with a posterior surgical approach. STUDY DESIGN: In vivo experimental pharmacokinetic study of cefuroxime concentrations in an acute preclinical porcine model. METHODS: The lumbar vertebral column was exposed from L1 to L5 in 8 female pigs. Microdialysis catheters were placed for sampling in the anterior column (vertebral body) and posterior column (posterior arch) within the same vertebra (L5). Cefuroxime (1.5 g) was administered intravenously. Microdialysates and plasma samples were continuously obtained over 8 hours. Cefuroxime concentrations were quantified by Ultra High Performance Liquid Chromatography Tandem Mass Spectrometry. The primary endpoint was the time above the cefuroxime clinical breakpoint minimal inhibitory concentration (T>MIC) for Staphylococcus aureus of 4 µg/mL. The secondary endpoint was tissue penetration (AUCtissue/AUCplasma). RESULTS: Mean T>MIC 4 µg/mL (95% confidence interval) was 123 min (105-141) in plasma, 97 min (79-115) in the anterior column and 93 min (75-111) in the posterior column. Tissue penetration (95% confidence interval) was incomplete for both the anterior column 0.48 (0.40-0.56) and posterior column 0.40 (0.33-0.48). CONCLUSIONS: T>MIC was comparable between the anterior and posterior column. Mean cefuroxime concentrations decreased below the clinical breakpoint minimal inhibitory concentration for S. aureus of 4 µg/mL after 123 minutes (plasma), 97 minutes (anterior column) and 93 minutes (posterior column). This is shorter than the duration of most lumbar spine surgeries, and therefore alternative dosing regimens should be considered in posterior open lumbar spine surgeries lasting more than 1.5 hours. CLINICAL SIGNIFICANCE: Open lumbar spine surgery often involves extensive soft tissue dissection, stripping and retraction of the paraspinal muscles which may impair the local blood flow exposing the lumbar vertebra to postoperative infections. A single intravenous administration of 1.5 g cefuroxime only provided sufficient prophylactic target tissue concentrations in the vertebra of the lumbar spine for up to 1.5 hours.

[Cervical spine fracture in a nine-year-old girl in spite of a normal CT scan].

In this case report, a nine-year-old girl was seen in the emergency department due to neck pain following a trampoline accident ten days ago. She had experienced paraesthesia in her left arm immediately after the accident, but these symptoms disappeared during the first day. A CT scan of the cervical spine was found to be normal. A supplementary MRI was done, showing compression fractures of four vertebrae C7-Th3 besides a torn interspinous ligament between C7 and Th1. The patient was kept in a neck collar for eight weeks. At the end of treatment, she was without any complaints.

[Metastatic spinal cord compression syndrome].

Metastatic spinal cord compression can be due to the debut of cancer or terminally advanced disease, and symptoms are pain, limb weakness, hypoaesthesia and sphincter dysfunction. In patients with a cancer history, metastatic spinal cord compression must be suspected, which is why MRI is necessary. In case of neurological impairment, the patient must consult surgical and oncologic specialists at a university hospital, who can offer the best treatment, i.e. surgery in combination with radiotherapy or radiotherapy alone. Treatment gives higher one-year survival, preserved ambulatory function, increased life quality and less pain, as summarised in this review.

Length of stay, readmission, and mortality after primary surgery for pediatric spinal deformities: a 10-year nationwide cohort study.

BACKGROUND CONTEXT: Extended length of stay (extLOS) and unplanned readmissions after first time pediatric spinal deformity surgery are a considerable challenge to both the patient and the health-care system. To our knowledge, only a limited number of nationwide studies reporting short-term comorbidity with complete follow-up exist. PURPOSE: The purpose of this study was to identify the postoperative complications leading to extLOS, readmissions, and mortality within 90 days after surgery. Furthermore, to identify risk factors for readmission. DESIGN: Retrospective national cohort study. PATIENT SAMPLE: A nationwide registry study including all pediatric spinal deformity patients (≤21 years of age) undergoing primary surgery during 2006-2015 (n=1,310). OUTCOME MEASURES: Reasons for extLOS and 90-day readmissions as well as mortality risk. METHODS: Patients were identified by procedure and diagnosis codes in the Danish National Patient Registry (DNPR). Data on length of stay (LOS), readmissions, and mortality within 90 days were retrieved from the DNPR. Patients were categorized in six groups according to etiology. Reasons for extLOS and readmission were collected from medical records and discharge summaries. RESULTS: For the 1,310 patients, the median LOS was 8 days (interquartile range 7-9). Etiologies were idiopathic deformity (53%), neuromuscular deformity (23%), congenital/structural deformity (9%), spondylolisthesis (7%), Scheuermann kyphosis (5%), and syndromic deformity (3%). A total of 274 (21%) patients had extLOS and the most common reason was pain/mobilization issues but with considerable variation between etiologies; Scheuermann kyphosis (91%), idiopathic (59%), syndromic (44%), spondylolisthesis (38%), and congenital (30%). Pulmonary complications were the primary reason for extLOS in the neuromuscular group (22%). The 90-day readmission rate was 6%; 67% of readmissions were medical, mainly infections unrelated to the surgical site (23%); 33% of readmissions were surgical and 14% of patients required revision surgery. Neuromuscular deformity, spondylolisthesis, Scheuermann kyphosis, and LOS >9 days were independent risk factors for readmission; odds ratio (OR) 4.4 (95% confidence interval: 2.2-9.1, p<.01), OR 3.0 (1.1-8.0, p=.03), OR 4.9 (1.7-13.6, p<.01), and OR 1.8 (1.0-3.1, p=.04), respectively. The 90-day mortality risk was 0.4%. CONCLUSIONS: In this nationwide cohort, pain/mobilization issues are the most common reason for extLOS. The most common reason for readmission is infection unrelated to the surgical site. Readmission after pediatric spinal surgery is related to the etiology and increased focus on patients operated for neuromuscular deformity, spondylolisthesis and Scheuermann kyphosis is warranted.

Revision risk after pediatric spinal deformity surgery: a nationwide study with 2-year follow-up.

BACKGROUND CONTEXT: Revision risk after pediatric spine surgery is not well established and varies between deformity etiologies. PURPOSE: To report the 2-year revision risk following surgery for primary pediatric spinal deformity in a nationwide cohort and to evaluate potential risk factors and reasons for revision surgery. DESIGN: Retrospective nationwide cohort study. PATIENT SAMPLE: A national registry study of all pediatric spinal deformity patients undergoing surgery during 2006-2015 (n=1310). OUTCOME MEASURES: Two-year revision risk. METHODS: All patients ≤21 years of age undergoing spinal deformity surgery in Denmark during 2006-2015 were identified by procedure and diagnosis codes in the Danish National Patient Registry (DNPR). Data on revision surgery were retrieved from the DNPR. Patients were categorized in six groups according to etiology. Medical records were reviewed for reason for revision in all patients. Potential risk factors for revision were assessed with multiple logistic regression analyses and included age, etiology, sex, Charlson comorbidity index (CCI), and growth-preserving treatment. RESULTS: Patients were categorized according to etiology: idiopathic deformity (53%), neuromuscular deformity (23%), congenital/structural deformity (9%), spondylolisthesis (7%), Scheuermann's kyphosis (5%), and syndromic deformity (3%). Of 1,310 included patients, 9.2% underwent revision surgery within 2 years and 1.5% was revised more than once. Median time to revision was 203 (interquartile range 35-485) days. The multivariable logistic regression found significantly higher odds ratio (OR) for revision in patients with growth-preserving treatment (OR=5.1, 95% confidence interval [CI] 2.6-10.1), congenital deformity (OR=2.7, 95% CI 1.3-5.3), spondylolisthesis (OR=3.5, 95% CI 1.9-6.7), Scheuermann kyphosis (OR=3.9, 95% CI 1.9-8.3), and CCI score ≥3 (OR=2.5 95% CI 1.1-5.6). The most common reason for revision was implant failure (32.5%) followed by residual deformity and/or curve progression (15.8%). CONCLUSIONS: In this nationwide study, the 2-year revision risk after primary pediatric spinal deformity surgery is 9.2%. Risk factors for revision are etiology of congenital deformity, spondylolisthesis, Scheuermann kyphosis as well as patients with growth-preserving treatment and higher CCI. The most common reason for revision is implant failure.

New growth rod concept provides three dimensional correction, spinal growth, and preserved pulmonary function in early-onset scoliosis.

INTRODUCTION: This study aims to describe a novel minimal invasive early-onset scoliosis (EOS) growth rod concept, the Cody Bünger (CB) Concept, which combines concave interval distraction and contralateral-guided growth with apical control and to investigate the 3D deformity correction, the spinal growth, and the pulmonary development. METHOD: A series of 38 children with progressive EOS and growth potential, receiving a highly specialized surgical treatment, including primary and conversion cases. Mean age was 10.2 years (4.4-15.8) with a mean follow-up of 5.6 years, and they underwent 168/184 open/magnetic lengthening procedures. Outcomes were as follows: scoliosis, kyphosis, and lordosis angles; apical rotation; spinal length; apical translation; coronal and sagittal vertical alignment; complications; and pulmonary function in a subgroup. RESULTS: Scoliosis improved from mean 76° (46-129) to 35° (8-74) post-op and was 42° (13-83) at end of treatment. Apical rotation was reduced by 30% but was partially lost during treatment. Thoracic kyphosis initially decreased by mean 15° and was partially lost during treatment. Lordosis was largely unaltered during treatment. Mean T1-S1 height increased from 30.7 cm (22.7-39.2) to 34.6 cm (27.8-45.1) postop and further increased to 38.5 cm (30.1-48.1) during treatment. This corresponded to a T1-S1 growth rate of 12 mm/year, and positive growth rates were found in all height parameters evaluated. Frontal balance and apical translation improved, whereas sagittal balance was unaltered. Complications occurred in 22/38 patients, and 11/38 had an unintended reoperation. Pulmonary function (FVC and FEV) increased but the relative lung function was unchanged. CONCLUSION: The new growth rod concept provided 3D correction and spinal growth at complication rates comparable with other growth-friendly techniques for EOS, while pulmonary function was preserved. Single magnetic rod distraction was incorporated successfully, replacing surgical elongations.

[Untreated os odontoideum may cause tetraplegia].

This review summarises the present, limited, knowledge of os odontoideum (OO). The prevalence is unknown, and the aetiology is widely debated, though irrelevant to management of the disease. Surgery of symptomatic patients is advocated, as there is more uncertainty about the treatment of asymptomatic patients. Diagnosis is obtained with plain X-ray. However, nowadays MRI and CT scanning are recommended for further clarification and judgement of the severity. Knowledge of OO is important to minimise misjudgement and consequently inappropriate treatment. It is recommended, that patients are examined by highly specialised spine doctors before further cervical manipulation due to the high risk of instability with potentially severe consequences.

[Spastic tetraparesis secondary to untreated os odontoideum].

This case report describes a 63-year-old woman, who had an undiscovered os odontoideum for three years and underwent therapy by a chiropractor and a physiotherapist, before the diagnosis was made. Os odontoideum is unknown to most doctors, and increased knowledge of the disease is of great importance, since inappropriate treatment in the form of manipulation and neck exercises might worsen the disease. In case of prolonged or uncharacteristic neck symptoms, the diagnosis should be considered, and a normal cervical X-ray would provide the diagnosis. If os odontideum is suspected, the patient should be referred to a highly specialised spine centre at a university hospital.

Does transforaminal lumbar interbody fusion produce leg pain?-Results from a RCT.

BACKGROUND: Transforaminal lumbar interbody fusion (TLIF) is presently the most used method to achieve lumbar interbody fusion worldwide. The special preparation and cage insertion imply a risk of an undesirable side effect in the form of residual neurogenic pain. This issue has not been investigated prior in a randomized clinical trial (RCT) set up. AIM: To test whether TLIFs had a higher incidence of leg pain in comparison to a common instrumented posterolateral fusion (PLF) and to test whether a higher occurrence of leg pain on the ipsilateral side in the TLIF group was present. METHODS: One hundred patients included in a RCT comparing TLIF and PLF fulfilled pain drawings and numeric rating scale (NRS) scale from 0 to 10 preoperatively, after 1 year, and after 2 years. Difference in pain appearance, type, localization, and intensity was compared between groups. RESULTS: A slightly higher number of patients in the TLIF group reported leg pain at 2 years follow-up: no leg pain, 47% (PLF) and 37% (TLIF); unilateral leg pain, 31% (PLF) and 25% (TLIF); bilateral leg pain, 22% (PLF) and 37% (TLIF), p = 0.270. Numbness and pins and needles on the anterior aspect of the lower leg were marked by 10% and 12% of TLIF patients compared to 6% and 4% in PLF patients p = 0.498/0.197. The ipsilateral side of cage insertion in the TLIF group was not a place for new leg pain compared to the contralateral side. CONCLUSION: The special surgical preparation used in TLIFs does not result in the development of new ipsilateral leg pain. However, a higher percentage of the patients in the TLIF group had new leg pain in comparison to PLF after 2 years.

[Ankylosing spinal fractures may result in perforation of oesophagus].

Oesophageal lesions due to spinal fractures are very rare and easily overlooked. In this case report a woman was involved in a minor car accident, and she was primarily examined at the accident and emergency department with no signs of fractures. Ten days later, she was readmitted due to high infection counts and back pain. She had an unstable fracture of Th4 and a perforation of the oesophagus due to ankylosing fractures. The case emphasises the need to pay attention to a possible development of secondary oesophageal perforation in ankylosing spines and unstable fractures, and the need for a special attention when examinating this group of patients.

Addition of TLIF does not improve outcome over standard posterior instrumented fusion. 5-10 years long-term Follow-up: results from a RCT.

PURPOSE: The use of inter-body device in lumbar fusions has been difficult to validate, only few long-term RCT are available. METHODS: Between 2003 and 2005, 100 patients entered a RCT between transforaminal lumbar inter-body fusion (TLIF) or posterolateral instrumented lumbar fusion (PLF). The patients suffered from LBP due to segmental instability, disc degeneration, former disc herniation, spondylolisthesis Meyerding grade <2. Functional outcome parameters as Dallas pain questionnaire (DPQ), SF-36, low back pain questionnaire (LBRS), Oswestry disability index (ODI) were registered prospectively, and after 5-10 years. RESULTS: Follow-up reached 93 % of available, (94 %, 44 in the PLF's and 92 %, 44 in the TLIF group p = 0.76). Mean follow-up was 8.6 years (5-10 years). Mean age at follow-up was 59 years (34-76 years p = 0.19). Reoperation rate in a long-term perspective was equal among groups 14 %, each p = 0.24. Back pain was 3.8 (mean) (Scale 0-10), TLIF (3.65) PLF (3.97) p = 0.62, leg pain 2.68 (mean) (Scale 0-10) 2.90 (TLIF) and 2.48 (PLF) p = 0.34. No difference in functional outcome between groups p = 0.93. Overall, global satisfaction with the primary intervention at 8.6 year was 76 % (75 % TLIF and 77 % PLF) p = 0.85. CONCLUSION: In a long-term perspective, patients with TLIF's did not experience better outcome scores.

Degenerative spondylolisthesis is associated with low spinal bone density: a comparative study between spinal stenosis and degenerative spondylolisthesis.

Spinal stenosis and degenerative spondylolisthesis share many symptoms and the same treatment, but their causes remain unclear. Bone mineral density has been suggested to play a role. The aim of this study was to investigate differences in spinal bone density between spinal stenosis and degenerative spondylolisthesis patients. 81 patients older than 60 years, who underwent DXA-scanning of their lumbar spine one year after a lumbar spinal fusion procedure, were included. Radiographs were assessed for disc height, vertebral wedging, and osteophytosis. Pain was assessed using the Low Back Pain Rating Scale pain index. T-score of the lumbar spine was significantly lower among degenerative spondylolisthesis patients compared with spinal stenosis patients (-1.52 versus -0.52, P = 0.04). Thirty-nine percent of degenerative spondylolisthesis patients were classified as osteoporotic and further 30% osteopenic compared to only 9% of spinal stenosis patients being osteoporotic and 30% osteopenic (P = 0.01). Pain levels tended to increase with poorer bone status (P = 0.06). Patients treated surgically for symptomatic degenerative spondylolisthesis have much lower bone mass than patients of similar age treated surgically for spinal stenosis. Low BMD might play a role in the development of the degenerative spondylolisthesis, further studies are needed to clarify this.