Lateral approach spine surgery provides effective interbody stabilization, and correction and indirect neural decompression with minimal-incision and less invasive surgery compared with conventional open anterior lumbar fusion. It may also avoid the trauma to paraspinal muscles or facet joints found with transforaminal lumbar interbody fusion and posterior lumbar interbody fusion. However, because lateral approach surgery is fundamentally retroperitoneal approach surgery, it carries potential risk to intra- and retroperitoneal structures, as seen in a conventional open anterior approach. There is an innovative lateral approach technique that reveals different anatomical views; however, it requires reconsideration of the traditional surgical anatomy in more detail than a traditional open anterior approach. The retroperitoneum is the compartmentalized space bounded anteriorly by the posterior parietal peritoneum and posteriorly by the transversalis fascia. The retroperitoneum is divided into three compartments by fascial planes: anterior and posterior pararenal spaces and the perirenal space. Lateral approach surgery requires mobilization of the peritoneum and its content and accurate exposure to the posterior pararenal space. The posterior pararenal space is confined anteriorly by the posterior renal fascia, anteromedially by the lateroconal fascia, and posteriorly by the transversalis fascia. The posterior renal fascia, the lateroconal fascia or the peritoneum should be detached from the transversalis fascia and the psoas fascia to allow exposure to the posterior pararenal space. The posterior pararenal space, however, does not allow a clear view and identification of these fasciae as this relationship is variable and the medial extent of the posterior pararenal space varies among patients. Correct anatomical recognition of the retroperitoneum is essential to success in lateral approach surgery. Spine surgeons must be aware that the retroperitoneal membrane and fascia is multilayered and more complex than is commonly understood. Preoperative abdominal images would facilitate more efficient surgical considerations of retroperitoneal membrane and fascia in lateral approach surgery.
Introduction: Osteoporosis is a pathological state with an unbalanced bone metabolism mainly caused by accelerated osteoporotic osteoclast activity due to a postmenopausal estrogen deficiency, and it causes some kinds of pain, which can be divided into two types: traumatic pain due to a fragility fracture from impaired rigidity, and pain derived from an osteoporotic pathology without evidence of fracture. We aimed to review the concepts of osteoporosis-related pain and its management.
Methods: We reviewed clinical and basic articles on osteoporosis-related pain, especially with a focus on the mechanism of pain derived from an osteoporotic pathology (i.e., osteoporotic pain) and its pharmacological treatment.
Results: Osteoporosis-related pain tends to be robust and acute if it is due to fracture or collapse, whereas pathology-related osteoporotic pain is vague and dull. Non-traumatic osteoporotic pain can originate from an undetectable microfracture or structural change such as muscle fatigue in kyphotic patients. Furthermore, basic studies have shown that the osteoporotic state itself is related to pain or hyperalgesia with increased pain-related neuropeptide expression or acid-sensing channels in the local tissue and nervous system. Traditional treatment for osteoporotic pain potentially prevents possible fracture-induced pain by increasing bone mineral density and affecting related mediators such as osteoclasts and osteoblasts. The most common agent for osteoporotic pain management is a bisphosphonate. Other non-osteoporotic analgesic agents such as celecoxib have also been reported to have a suppressive effect on osteoporotic pain.
Conclusions: Osteoporotic pain has traumatic and non-traumatic factors. Anti-osteoporotic treatments are effective for osteoporotic pain, as they improve bone structure and the condition of the pain-related sensory nervous system. Physicians should always consider these matters when choosing a treatment strategy that would best benefit patients with osteoporotic pain.
Study Design: A prospective cohort study was conducted on patients with anterior cervical decompression and fusion (ACDF) with a polyetheretherketone cage (PEEKc).
Background: Advantages of a PEEKc have been proposed in the study. However, benefits of using a PEEKc in ACDF are still controversial.
Objective: To investigate the advantages of a PEEKc in ACDF.
Materials and Methods: A total of 27 patients was enrolled in the study. The mean age of patients was 55±10 years (mean±standard deviation). The mean duration of symptoms was 17±21 months. Surgery was conducted at C3/4 in 1, C4/5 in 3, C5/6 in 11, C6/7 in 9, C7/T1 in 2, and C5/6/7 in 1 patient. The mean follow-up period was 2.1±1.3 years. Clinical outcomes were analyzed by the Japanese Orthopedic Association Scores (JOA scores) and its recovery rate. Perioperative complications were also investigated. Radiologically, studies were conducted on interbody lordotic angle (IBLA), interbody height (IBH), and bone fusion rates.
Results: The JOA score was 14.7±1.4 preoperatively and 16.3±1.3 at the final follow-up. A significant improvement was observed (p<0.05). The mean recovery rate of JOA scores was 74.0±25.0%. The preoperative IBLA was 0.5±6.1°. The mean IBLA at the final follow-up was 1.9±5.6°. The preoperative IBH was 34.2±3.5 mm. The mean IBH at the final follow-up was 34.3±3.5 mm. No significant improvement in IBLA and IBH was observed. A complete union rate at 1 year and 2.3 years (range, 2.0-6.0) after surgery was 29% (8/28 segments) and 61% (11/18 segments). No major complications were observed.
Conclusions: Despite an unsatisfactory bone union rate and no significant improvement in IBLA and IBH at the final follow-up, ACDF with a PEEKc clinically provided a stable outcome with less surgical invasion and minor donor-site morbidity.
Introduction: Although initial treatments for pyogenic spondylitis include conservative approaches such as rest and antibiotics, some cases are refractory to conservative therapy. The objective of this study was to clarify the predictors for achievement of C-reactive protein (CRP) normalization in pyogenic spondylitis by conservative therapy.
Methods: In the present study, we enrolled 83 patients (51 men and 32 women) with conservatively treated pyogenic spondylitis from 2006 to 2015. Multiple logistic regression analysis was used to examine the association of achievement of CRP normalization with the number of infected vertebrae, bacterial strain, blood data, and the expansion of abscess to the epidural space by using functional magnetic resonance imaging.
Results: We found significant differences in the subjects with and without achievement of CRP normalization with respect to age, the number of affected vertebrae, ratio of resistant pathogenic bacteria, ratio of expansion of abscess to the epidural space, and blood data such as Hb, ALB, eGFR, Cr, and ALP levels.
After adjustment for age and sex, the number of infected vertebral bodies, resistant bacteria, expansion of abscess to the epidural space, and Hb level showed significant associations with the normalization of CRP. In addition, we used multiple logistic regression analysis with age, sex, number of infected vertebral bodies, resistant bacteria, expansion of abscess to the epidural space, and serum Hb level as explanatory variables. We found that expansion of the abscess to the epidural and paravertebral spaces was significantly associated with the normalization of CRP level.
Conclusions: The number of infected vertebral bodies, resistant strains of pathogenic bacteria, expansion of abscess to the epidural and paravertebral spaces, and serum Hb level predicts the prognosis of patients with pyogenic spondylitis. Particularly, expansion of abscess to the epidural and paravertebral spaces was strongly associated with the achievement of CRP normalization.
Introduction: Modic type 1 changes around the vertebral endplate of the lumbar spine are well known to indicate inflammation; however, the clinical significance of similar SCs of the posterior elements has not been elucidated.
Methods: Six hundred ninety-eight MRIs of patients with complaints of low back/leg pain were retrospectively examined. Target SCs in this study were hypointensity on T1-WI and hyperintensity on T2-WI or short tau inversion recovery sequences showing the same signal patterns seen in Modic type 1 change of the lumbar posterior elements. We analyzed the (1) Prevalence, symptom, and age distribution of SCs, (2) Localization of SCs and their association with Modic type 1 changes, (3) Spinal level distribution of SCs, (4) Association between SCs and disc degeneration of the affected spinal level, and (5) Association between SCs and radiological changes (spondylolisthesis, scoliosis).
Results: (1) Among 698 adult patients, 36 (16 men, 20 women) exhibited SCs (5.2%). No SCs were identified in patients age <40 years. (2) Of the 36 SCs, 9 (25%) were localized at a single spinal level, while 27 (75%) were found at neighboring spinal levels across the facet joint. Thirteen SCs (36.1%) had continuity with Modic type 1 changes around the vertebral endplate, while 23 (63.9%) were localized to the posterior elements. (3) SCs were frequently identified in the lower lumbar spine below the L4 level. (4) More than 80% of the SCs involved disc degeneration. (5) Spondylolisthesis was associated with 93% of SCs in double-level, and scoliosis was associated with SCs in unilateral side.
Conclusion: The prevalence of SCs in symptomatic adults was 5.2%. On the basis of observed disc degeneration, 75% of SCs were considered to indicate inflammation or bone marrow edema around the facet joint.
Introduction: This study aimed to evaluate morphological changes in the L5 nerve roots in control and symptomatic patients using magnetic resonance myelography [MRM]. Moreover, the utility of MRM for the diagnosis of intraforaminal or extraforaminal lesions in patients with L5 radiculopathy was evaluated using healthy subjects as controls.
Methods: Of 270 subjects who underwent MRM of the lumbar spine at our institution between April 2007 and December 2010, 135 patients (78 men and 57 women; average age: 61.3 years) with no history of spinal surgeries and nerve roots without infections, tumors, or malformations were selected for this study.
The end-point measurements included the bifurcation angle of inclination (proximal tilting angle [PTA]) of the L5 nerve root as observed via MRM, lateral angle of inclination (lateral tilting angle [LTA]), bifurcation diameter (proximal nerve root width [PW]), and dorsal root ganglion (DRG) diameter (DRG width [DW]). DW ratio was then calculated for healthy controls and symptomatic subjects. We measured each parameter using the image information unification system ShadeQuest (Yokogawa, Tokyo, Japan). Two spinal surgeons conducted the magnetic resonance imaging evaluation.
Results: Swelling of the L5 DRG was detected in cases with intraforaminal or extraforaminal stenosis. With regard to the cutoff value of 6.5 mm for L5 DW, foraminal stenosis can be confirmed if DW is ≥6.5 mm or more via MRM. In cases where L5 DRG was swollen to ≥1.2 times the size in healthy subjects, L5 radiculopathy with foraminal lesions can be diagnosed.
Conclusions: Our findings indicated that 3D MRM is a noninvasive technique and a useful tool for the diagnosis of intraforaminal or extraforaminal lesions in the lumbar spine. Therefore, it can be combined with other diagnostic methods used for the identification of intraforaminal or extraforaminal L5 nerve root lesion.
Object: Low back pain (LBP) attributable to fusion failure, implant failure, infection, malalignment, or adjacent segment disease may persist after lumbar fusion surgery (LFS). Superior cluneal nerve (SCN) entrapment neuropathy (SCNEN) is a clinical entity that can produce LBP. We report that SCNEN treatment improved LBP in patients who had undergone LFS.
Methods: Between April 2012 and August 2015, we treated 8 patients (4 men and 4 women ranging in age from 38 to 88 years; mean age, 69 years) with SCNEN for their LBP after LFS. Our criteria for the diagnosis of SCNEN included a trigger point over the posterior iliac crest 7 cm from the midline and numbness and radiating pain in the SCN area upon compression of the trigger point. Symptom relief was obtained in more than 75% of patients within 2 h of inducing a local nerve block at the trigger point in the buttocks. The mean postoperative follow-up period was 28 months (range, 9-54 months).
Results: LBP was unilateral in 3 and bilateral in 5 patients. The senior author (T.I.) operated all patients for SCNEN under local anesthesia because they reported recurrence of pain after the analgesic effect of repeat injections wore off. This led to a significant improvement of their LBP.
Conclusions: SCNEN should be considered in patients reporting LBP after LFS. Treatment of SCNEN may be a useful option in patients with failed back surgery syndrome after LFS.