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Objective: This report describes a minimally invasive lumbar foraminotomy technique that can be applied in patients who underwent complex spine decompression procedures or in patients with severe foraminal stenosis., Methods: Awake, endoscopic decompression surgery was performed in 538 patients over a 5-year period between 2014 and 2019. Transforaminal endoscopic foraminal decompression surgery using a high-speed endoscopic drill was performed in 34 patients who had previously undergone fusions at the treated level., Results: At 2-year follow-up, the mean (± SD) preoperative visual analog scale score for leg pain and the Oswestry Disability Index improved from 7.1 (± 1.5) and 40.1% (± 12.1%) to 2.1 (± 1.9) and 13.6% (± 11.1%)., Conclusions: A minimally invasive, awake procedure is presented for the treatment of severe lumbar foraminal stenosis in patients with lumbar radiculopathy after lumbar fusion.

Advancements in the understanding of adult spinal deformity have led to a greater awareness of the role of the pelvis in maintaining sagittal balance and alignment. Pelvic incidence has emerged as a key radiographic measure and should closely match lumbar lordosis. As proper measurement of the pelvic incidence requires accurate identification of the S-1 endplate, lumbosacral transitional anatomy may lead to errors. The purpose of this study is to demonstrate how lumbosacral transitional anatomy may lead to errors in the measurement of pelvic parameters. The current case highlights one of the potential complications that can be avoided with awareness. The authors report the case of a 61-year-old man who had undergone prior lumbar surgeries and then presented with symptomatic lumbar stenosis and sagittal malalignment. Radiographs showed a lumbarized S-1. Prior numbering of the segments in previous surgical and radiology reports led to a pelvic incidence calculation of 61°. Corrected numbering of the segments using the lumbarized S-1 endplate led to a pelvic incidence calculation of 48°. Without recognition of the lumbosacral anatomy, overcorrection of the lumbar lordosis might have led to negative sagittal balance and the propensity to develop proximal junction failure. This case illustrates that improper identification of lumbosacral transitional anatomy may lead to errors that could affect clinical outcome. Awareness of this potential error may help improve patient outcomes.

Object: The authors report their experience in treating 21 patients by using a novel form of treatment of lumbar degenerative disease that leads to canal stenosis. The surgery involved distraction of the facets using specially designed Goel intraarticular spacers and was aimed at arthrodesis of the spinal segment in a distracted position. The operation is based on the premise that subtle and longstanding facet instability, joint space reduction, and subsequent facet override had a profound and primary influence in the pathogenesis of degenerative lumbar canal stenosis. The surgical technique and the rationale for treatment are discussed., Methods: Between April 2006 and January 2011, 21 cases of lumbar degenerative disease resulting in characteristic lumbar canal stenosis were treated in the authors' department with the proposed technique. The patients were prospectively analyzed. There were 15 men and 6 women who ranged in age from 48 to 71 years (mean 58 years). Nine patients underwent 1-level and 12 patients underwent 2-level treatment. Surgery involved wide opening of the articular joint, denuding of the articular capsule/endplate cartilage, distraction of the facets, and forced impaction of Goel intraarticular spacers. Bone graft pieces obtained by sectioning the spinous processes were placed within and over the joint and in the midline over the adequately prepared host area of laminae. The Oswestry Disability Index and visual analog scale were used to clinically assess the patients before and after surgery and at follow-up. The alterations in the physical architecture of spinal canal and intervertebral foramen dimensions were evaluated before and after placement of the intrafacet implant and after at least 6 months of follow-up., Results: All patients had varying degrees of relief from symptoms of local back pain and radiculopathy. Impaction of spacers within the facet joints resulted in an increase in the spinal canal and intervertebral root canal dimensions (mean 2.33 mm), reduction of buckling of the ligamentum flavum, and reduction of the extent of bulge of the disc into the spinal canal. The procedure resulted in firm stabilization and fixation of the spinal segment and provided a ground for arthrodesis. No patient worsened neurologically after treatment. During the follow-up period, all patients had evidence of segmental bone fusion. No patient underwent reexploration or further surgery of the lumbar spine., Conclusions: Impaction of the spacers within the articular cavity after facet distraction resulted in reversal of several effects of spine degeneration that had caused spinal and root canal stenosis. The safe, firm, and secure stabilization at the fulcrum of lumbar spinal movements provided a ground for segmental spinal arthrodesis. The immediate postoperative and lasting recovery from symptoms suggests the validity of the procedure.

Object: The achondroplastic spinal canal is narrow due to short pedicles and a small interpedicular distance. Compression of neural structures passing through this canal is therefore regularly encountered but rarely described. Symptomatology, radiological evaluation, and treatment of 20 patients with achondroplasia who underwent decompression of the thoracic spinal cord are described and outcome is correlated with the size of the spinal canal and the thoracolumbar kyphotic angle., Methods: Scores from the modified Japanese Orthopaedic Association scale, Nurick scale, European Myelopathy scale, Cooper myelopathy scale for lower extremities, and Odom criteria before and after surgery were compared. Magnetic resonance imaging was evaluated to determine the size of the spinal canal, spinal cord compression, and presence of myelomalacia. The thoracolumbar kyphotic angle was measured using fluoroscopy., Results: Patient symptomatology included deterioration of walking pattern, pain, cramps, spasms, and incontinence. Magnetic resonance images of all patients demonstrated spinal cord compression due to degenerative changes. Surgery resulted in a slight improvement on all the ranking scales. Surgery at the wrong level occurred in 15% of cases, but no serious complications occurred. The mean thoracolumbar kyphotic angle was 20°, and no correlation was established between this angle and outcome after surgery. No postoperative increase in this angle was reported. There was also no correlation between size of the spinal canal and outcome., Conclusions: Decompressive surgery of the thoracic spinal cord in patients with achondroplasia can be performed safely if anatomical details are taken into consideration. Spondylodesis did not appear essential. Special attention should be given to the method of surgery, identification of the level of interest, and follow-up of the thoracolumbar kyphotic angle.

Object: Cervical stenotic myelopathy due to spondylosis or ossification of the posterior longitudinal ligament is often treated with laminoplasty or cervical laminectomy (with fusion). The goal of this study was to compare outcomes, radiographic results, complications, and implant costs associated with these 2 treatments., Methods: The authors analyzed the records of 56 patients (age range 42–81 years) who were surgically treated for cervical stenosis. Of this group, 30 underwent laminoplasty and 26 underwent laminectomy with fusion. Patients who had cervical kyphosis or spondylolisthesis were excluded. An average of 4 levels were instrumented in the laminoplasty group and 5 levels in the fusion group (p < 0.01). Forty-two percent of the fusions crossed the cervicothoracic junction, but no laminoplasty instrumentation crossed the cervicothoracic junction, and it only reached C-7 in one-third of the cases. Preoperative and postoperative Nurick grades and modified Japanese Orthopaedic Association (mJOA) scores were obtained. Outcomes were also assessed with neck pain visual analog scale (VAS) scores and the Odom outcome criteria. Postoperative length of stay, complications, and implant costs were calculated., Results: The mean duration of follow-up, average patient age, and length of hospital stay were similar for both groups. The mean Nurick scores were also similar in the 2 groups and improved an average of 1.4 points in both (p < 0.01 for preoperative-postoperative comparison in each group). The mean mJOA scores improved 2.7 points in laminoplasty patients and 2.8 points in fusion patients (p < 0.01 for each group). The mean VAS scores for neck pain did not change significantly in the laminoplasty cohort (3.2 ± 2.8 [SD] preoperatively vs 3.4 ± 2.6 postoperatively, p = 0.50). In the fusion cohort, the mean VAS scores improved from 5.8 ± 3.2 to 3.0 ± 2.3 (p < 0.01). Excellent or good Odom outcomes were observed in 76.7% of the patients in the laminoplasty cohort and 80.8% of those in the fusion cohort (p = 0.71). In the fusion group, complications were twice as common and implant costs were nearly 3 times as high as in the laminoplasty group. When cases involving fusions crossing the cervicothoracic junction were excluded, analysis showed similar complication rates in the 2 groups., Conclusions: Patients treated with laminoplasty and patients treated with laminectomy and fusion had similar improvements in Nurick scores, mJOA scores, and Odom outcomes. Patients who underwent fusion typically had higher preoperative neck pain scores, but their neck pain improved significantly after surgery. There was no significant change in the neck pain scores of patients treated with laminoplasty. Our series suggests cervical fusion significantly reduces neck pain in patients with stenotic myelopathy, but that the cost of the implant and rate of reoperation are greater than in laminoplasty.

Object: Surgical outcome and radiographic changes after microsurgical bilateral decompression via a unilateral approach (MBDU) for lumbar spinal canal stenosis during midterm follow-up periods (> 2 years) have not been reported. The authors retrospectively investigated surgical outcomes after MBDU in patients with lumbar degenerative spondylolisthesis with stenosis in comparison with patients with degenerative stenosis during a minimum follow-up period of 2 years. Radiographic changes at the affected intervertebral level were analyzed during that follow-up period., Methods: Forty-eight patients (23 in the spondylolisthesis group, 25 in the degenerative stenosis group) were included in the study. The average follow-up period was 46 months (range 24-71 months). Surgical outcome was evaluated using the Neurogenic Claudication Outcome Score (NCOS) and the Oswestry Disability Index (ODI). Additionally, the back pain score within the NCOS was also compared. There were no statistically significant differences between the spondylolisthesis group and the degenerative stenosis group with regard to sex, age, follow-up period, operating time, blood loss, surgical sites, approach side, preoperative NCOS, preoperative back pain score, and preoperative ODI. Comparisons were also made between groups using 2 satisfaction measurements at the last follow-up visit. Radiographically, intervertebral angles of 80 sites and slip percentages of 24 sites were measured preoperatively and at the last follow-up., Results: No patient in either group had additional surgery in the lumbar spine, including fusion procedures. The NCOS, back pain score, and ODI had significantly improved at the last follow-up in both groups. There were no significant differences between the 2 groups in these 3 parameters and the 2 satisfaction measurements at the last follow-up, although those for the spondylolisthesis group indicated a somewhat worse outcome. Intervertebral angles, dynamic intervertebral angles, and dynamic slip percentage did not significantly change after surgery, whereas only slip percentage significantly increased postoperatively (p = 0.0319)., Conclusions: A satisfactory outcome of MBDU persisted for a period longer than 2 years for patients with degenerative spondylolisthesis with stenosis as well as for those with degenerative stenosis. Radiographically in both groups this less invasive procedure was not likely to result in postoperative dynamic instability at the affected level, although the slippage progressed in the spondylolisthesis group.

The incidence rate of kyphosis of the cervical spine after a laminectomy can be as high as 20% after a multilevel laminectomy. The loss of the posterior tension band leads to increased load on the vertebral body and discs, leading to further degenerative changes and kyphotic deformities. The initial decompression of the spinal cord disappears as the cord is stretched over the anterior lesions. Muscle damage and facet degeneration from prior surgery contribute to additional pain, muscle spasm, and motion. Occasionally prior surgical fusion that fails to address the kyphosis or spontaneous fusion in a kyphotic position (observed more in laminectomies performed in the growing spine) can result in a challenging rigid deformity with anterior vertebral body and lateral mass facet fusion. For this fixed deformity, anterior and posterior release are often necessary for restoration of lordosis, which can result in the need for a 540 degrees procedure. In this report the authors describe an anterior technique for simultaneous anterior and posterior lateral mass release. The vertebral artery is mobilized using this technique, allowing for its lateral retraction. The nerve roots are visualized and retracted superiorly and inferiorly. The lateral mass and facets can then be accessed anteriorly using an osteotome or drill for the release. The authors illustrate this technique in a patient who developed fixed scoliosis and kyphosis of the cervical spine after surgery for degenerative disc disease. To the authors' knowledge, this is the first report of this technique.

Object: The purpose of this study was to evaluate the correlation between adjacent-segment degeneration (ASD) and pelvic parameters in the patients with spondylolytic spondylolisthesis. Sagittal balance is the most important risk and prognostic factor in the development of ASD. The pelvic incidence angle (PIA) is an important anatomical parameter in determining the sagittal curvature of the spine and in the individual variability of the sacral slope and the lordotic curve. Thus, the authors evaluated the relationship between the pelvic parameters and the ASD. Methods. Among 132 patients with spondylolytic spondylolisthesis who underwent surgery at their institution, the authors selected patients in whom a one-stage, single-level, 360 degrees fixation procedure was performed for Grade I spondylolisthesis and who underwent follow-up for more than 1 year. Parameters in 34 patients satisfied these conditions. Of the 34 patients, seven had ASD (Group 1) and 27 patients did not have ASD (Group 2). The investigators measured degree of spondylolisthesis, lordotic angle, sacral slope angle (SSA), pelvic tilt angle (PTA), PIA, and additional parameters pre-and postoperatively. The radiographic data were reviewed retrospectively. Results. The population consisted of nine men and 25 women whose mean age was 48.9 +/- 9 years (+/- standard deviation) (range 28-65 years). Seven patients developed ASD after undergoing fusion. Of all the parameters, pre- and postoperative degree of spondylolisthesis, segmental lordosis, lordotic angle, SSA, preoperative PTA, and preoperative PIA did not differ significantly between the two groups; only postoperative PTA and PIA were significantly different. Conclusions. The development of ASD is closely related to postoperative PIA and PTA, not preoperative PIA and PTA. The measurement of postoperative PIA can be used as a new indirect method to predict the ASD.

Object: As increasing numbers of patients receive long-term hemodialysis, the number of reports regarding hemodialysis-related cervical spine disorders has also increased. However, there have been few reports summarizing the surgical results in patients with these disorders. The objective of this study was to evaluate the long-term follow up and clinical results after surgical treatment of cervical disorders in patients undergoing hemodialysis., Methods: Seventeen patients in whom surgery was performed for cervical spine disorders while they received long-term hemodialysis therapy were enrolled in this study. Of these, 15 underwent follow-up review for more than 3 years after surgery, and these represent the study population. The remaining two patients died of postoperative sepsis. The average follow-up period was 120 months. Five patients without spinal instability underwent spinal cord decompression in which bilateral open-door laminoplasty was performed. Ten patients with destructive spondyloarthropathy (DSA) underwent reconstructive surgery involving pedicle screw (PS) fixation. In eight patients in whom posterior instrumentation was placed, anterior strut bone grafting was performed with autologous iliac bone to treat anterior-column destruction. Marked neurological recovery was obtained in all patients after the initial surgery. In the mobile segments adjacent to the site of previous spinal fusion, the authors observed progressive destructive changes with significant instability in four patients (40%) who underwent circumferential spinal fusion. No patients required a second surgery after laminoplasty for spinal canal stenosis without DSA changes., Conclusions: Cervical PS-assisted reconstruction provided an excellent fusion rate and good spinal alignment. During the long-term follow-up period, however, some cases required extension of the spinal fusion due to the destructive changes in the adjacent vertebral levels. Guidelines or recommendations to overcome these problems should be produced to further increase the survival rates of patients undergoing hemodialysis.

Object: Spinal stenosis due to lumbar ossified lesions is a rare pathological entity. The authors retrospectively evaluated the clinical features and surgical results associated with cases involving lumbar ossified lesion-induced stenosis., Methods: Data obtained in 20 surgically treated patients with lumbar hyperostotic spinal stenosis were included. To evaluate the background of the disease, body mass index and general complications were assessed. Whole-spine radiological examination was conducted. The presence of ossification of the posterior longitudinal ligament or ossification of the ligamentum flavum was evaluated. Surgical results were classified according to the Japanese Orthopaedic Association (JOA) scale. In the patients in whom neurological deterioration was observed during follow up, the causes of deterioration were reviewed. Seven patients (35%) were obese and six patients (30%) suffered diabetes mellitus. Twelve patients harbored coexisting cervical and/or thoracic ossified lesions. The overall mean JOA score improved from 10.2 to a peak of 22.5; at last follow-up examination the mean JOA score was 20.9. In female and older patients with a long history of preoperative symptoms, a low preoperative JOA score, and other spinal lesions, recovery tended to be poorer. Recovery was poor in one patient, and neurological deterioration due to coexisting ossified spinal lesions occurred in another patient during the follow-up period., Conclusions: Because coexisting ossified lesions were frequently seen, whole-spine analysis is recommended. Early diagnosis and appropriate treatment are important to achieve a better surgical outcome.

Despite the fact that gout is a common metabolic disorder, because its involvement of the axial skeleton is rare the diagnosis is often delayed, even in patients with long-standing gout who present with neurological deficits. The authors report the case of a woman with a history of extensive gout, emphasizing the clinical, radiological, and pathological features of a lumbar spinal stenosis.

The authors report two cases of nodular calcium pyrophosphate dihydrate (CPPD) crystal deposition close to the thoracic neural foramen, which caused chronic radiculopathy. Preoperatively, the lesions were interpreted as calcified disc herniations. Both patients underwent surgery in which an extended transfacet pedicle-sparing approach was used. Incision of the posterior longitudinal ligament released soft degenerated material. In both cases, histological examination showed abundant degenerative debris along with CPPD crystals. Spinal CPPD deposition is a comparatively rare disease that almost invariably involves the posterior aspect of the spinal canal, typically the ligamentum flavum. The exceptional foraminal location of the lesions reported here, combined with the surgical findings, indicated that the CPPD crystals were deposited on a laterally herniated disc fragment. A distinctive feature in both cases was the soft consistency of the resected tissue. The consistency of the disc material and the location of the lesion in the axial plane (that is, median compared with lateral) are key factors in determining the optimal surgical approach to thoracic disc herniations. In describing consistency, terms such as "calcified" and "hard" have been used interchangeably in the literature. In the cases reported here, what appeared on computerized tomography and magnetic resonance imaging studies to be densely calcified lesions were shown intraoperatively to be soft herniations. The authors' experience underscores that not all densely calcified herniated discs are hard. Although detection of this discrepancy would have left surgical planning for the lateral disc herniations unchanged, it could have altered planning for centrally or centrolaterally located disc herniations.