Seung-Chul Rhim

Clinical Outcomes and Complications after Pedicle Subtraction Osteotomy for Fixed Sagittal Imbalance Patients : A Long-Term Follow-Up Data

OBJECTIVE Clinical, radiographic, and outcomes assessments, focusing on complications, were performed in patients who underwent pedicle subtraction osteotomy (PSO) to assess correction effectiveness, fusion stability, procedural safety, neurological outcomes, complication rates, and overall patient outcomes. METHODS We analyzed data obtained from 13 consecutive PSO-treated patients presenting with fixed sagittal imbalances from 1999 to 2006. A single spine surgeon performed all operations. The median follow-up period was 73 months (range 41-114 months). Events during perioperative course and complications were closely monitored and carefully reviewed. Radiographs were obtained and measurements were done before surgery, immediately after surgery, and at the most recent follow-up examinations. Clinical outcomes were assessed using the Oswestry Disability Index and subjective satisfaction evaluation. RESULTS Following surgery, lumbar lordosis increased from -14.1 degrees +/- 20.5 degrees to -46.3 degrees +/- 12.8 degrees (p < 0.0001), and the C7 plumb line improved from 115 +/- 43 mm to 32 +/- 38 mm (p < 0.0001). There were 16 surgery-related complications in 8 patients; 3 intraoperative, 3 perioperative, and 10 late-onset postoperative. The prevalence of proximal junctional kyphosis (PJK) was 23% (3 of 13 patients). However, clinical outcomes were not adversely affected by PJK. Intraoperative blood loss averaged 2,984 mL. The C7 plumb line values and postoperative complications were closely correlated with clinical results. CONCLUSION Intraoperative or postoperative complications are relatively common following PSO. Most late-onset complications in PSO patients were related to PJK and instrumentation failure. Correcting the C7 plumb line value with minimal operative complications seemed to lead to better clinical results.

The Time Course of Range of Motion Loss After Cervical Laminoplasty: A Prospective Study With Minimum Two-Year Follow-up

Study Design. A prospective study. Objective. To identify the time-dependent change in range of motion (ROM) after cervical laminoplasty. Summary of Background Data. Although numerous studies have reported on the loss of flexion/extension ROM associated with laminoplasty, few have reported on the time course of this loss of motion. Methods. Twenty-three patients who received unilateral open-door laminoplasties, including miniplate fixation over 2 levels, were serially evaluated at regular set intervals after surgery. The mean follow-up period was 26.78 months (range: 24–41 months). Twelve patients had OPLL and 11 patients had cervical spondylotic myelopathy. Enrolled patients were divided into 2 groups (ossification of posterior longitudinal ligament [OPLL] and cervical spondylotic myelopathy) to compare the ROM between the OPLL and the spondylosis patients. We evaluated the time-dependent neck ROM changes by taking neutral, flexion, and extension radiographs before surgery and at 1, 3, 6, 9, 12, 18, and 24 months after surgery. Postoperative neck and arm pain was evaluated using a numerical rating scale. Results. The preoperative, and 1-, 3-, 6-, 9-, 12-, 18-, and 24-month postoperative ROM figures were 37.8° ± 14.6°, 34.1° ± 12.9°, 35.0° ± 12.3°, 30.3° ± 13.0°, 28.6° ± 15.1°, 27.3° ± 12.4°, 26.1° ± 14.8°, and 25.9° ± 13.2°, respectively, and at the most recent follow-up, ROM was 25.8 ± 15.2°. Thus, the mean ROM decreased by 10.1° ± 9.5° (31.66%) after surgery (P = 0.002). In OPLL group, we observed a more limited cervical ROM than in cervical spondylotic myelopathy group (35.3% vs. 29.2%). However, the rate of ROM reduction slowed with time in both groups (P = 0.000). Postoperative axial pain did not correlate with the degree of serial cervical ROM. Conclusion. The results suggest that the loss of cervical ROM is time-dependent and plateaus by18 months after surgery, with no further decreases thereafter.

Combined motor and somatosensory evoked potential monitoring for intramedullary spinal cord tumor surgery: correlation of clinical and neurophysiological data in 17 consecutive procedures

The primary objective of neurophysiologic monitoring during surgery is to prevent permanent neurological sequelae. We prospectively evaluated whether the combined use of somatosensory- and motor-evoked potential (SEP/MEP) for intramedullary spinal cord tumor (IMSCT) surgery may be beneficial. Combined SEP/MEP monitoring was attempted in 20 consecutive procedures for IMSCT operations. Trains of transcranial electric stimulation over the motor cortex were used to elicit MEPs from limb target muscles. The tibial and median nerves were stimulated to record SEP. The operation was paused or the surgical strategy was modified in every case of significant SEP/MEP changes. Combined SEP/MEP recording was successfully achieved in 17 of 20 (85%) operations. In 3 of 17 operations, SEP and MEP were stable, and all patients remained neurologically intact after surgery. Significant MEP changes were recorded in 12 operations (70%). In 7 of these 12 operations, MEP recovered to some extent after surgical intervention, and these patients showed no neurological changes. In the remaining 5 operations, MEP did not recover and the patients had a transient (n = 2) or a permanent (n = 1) motor deficit. Significant SEP changes with stable MEP were related to a transient hypesthesia. Combined SEP/MEP monitoring provided higher sensitivity, and higher positive and negative predictive value than single-modality techniques. Detection of MEP changes and adjustment of surgical strategy may prevent irreversible pyramidal tract damage.

Range of motion loss after cervical laminoplasty: a prospective study with minimum 5-year follow-up data.

BACKGROUND CONTEXT Although numerous studies have reported on the loss of flexion-extension range of motion (ROM) associated with laminoplasty, few have reported on the time course of this loss of motion for a long-term follow-up period. PURPOSE We previously reported our early data on postlaminoplasty cervical ROM. In this article, we describe our minimum 5-year follow-up data to identify the time-dependent change in ROM after cervical laminoplasty. STUDY DESIGN A prospective cohort study. PATIENT SAMPLE The procedure was performed in 23 patients. Eighteen patients with a minimum 5-year follow-up were included in the study. OUTCOME MEASURES The time-dependent neck ROM changes observed in the neutral, flexion, and extension radiographs were used to measure the radiological outcome. The Japanese Orthopaedic Association classification and a numerical rating scale of axial neck pain and arm pain were used to evaluate clinical outcome. METHODS Twenty-three patients who received unilateral open-door laminoplasties, including miniplate fixation over three levels, were serially evaluated at regular set intervals postoperatively. Eighteen patients with a minimum 5-year follow-up were included in the study. The mean follow-up period was 68.1 months (range, 60-78 months). Nine patients had ossification of posterior longitudinal ligament (OPLL) and nine patients had cervical spondylotic myelopathy (CSM). Enrolled patients were divided into subgroups (OPLL vs. CSM; autofusion vs. nonautofusion) to compare the ROM between the groups. We evaluated the time-dependent neck ROM changes by taking neutral, flexion, and extension radiographs preoperatively and at 1, 3, 6, 9, 12, 18, and 24 months postoperatively. Follow-up radiographs were taken annually after a 2-year follow-up. RESULTS The preoperative and 1-, 3-, 6-, 12-, 24-, 36-, 48-, and 60-month postoperative ROM figures were 39.9 ± 11.2°, 35.0 ± 9.2°, 33.0 ± 11.0°, 30.1 ± 10.4°, 25.8 ± 13.1°, 24.7 ± 10.0°, 23.8 ± 6.5°, 24.6 ± 8.3°, and 23.6 ± 9.4°, respectively, and at the most recent follow-up, ROM was 24.5 ± 10.1°. Thus, the mean ROM decreased by 15.4 ± 8.4° (38.5%) by the last follow-up (p<.0001). In the OPLL group, we observed a more limited cervical ROM than in the CSM group (47.2% vs. 72.7%). As expected, in the laminar autofusion group, the ROM decreased significantly (55.6% decrease), whereas in the nonautofusion group, the ROM decreased less significantly (13.4% decrease) at the last follow-up. Postoperative axial pain did not correlate with the cervical ROM. CONCLUSIONS These results suggest that the loss of cervical ROM after laminoplasty is time-dependent, and patients with OPLL and laminar autofusion had less ROM. Postlaminoplasty ROM reduction can recover after several years, unless laminar autofusion occurs.

Clinical Outcomes and Radiologic Changes After Microsurgical Bilateral Decompression by a Unilateral Approach in Patients With Lumbar Spinal Stenosis and Grade I Degenerative Spondylolisthesis With a Minimum 3-Year Follow-Up.

Study Design:A retrospective study. Objective:To analyze the clinical outcomes and radiologic changes after microsurgical bilateral decompression via a unilateral approach in patients with lumbar spinal stenosis (LSS) and degenerative spondylolisthesis (DS). Summary of Background Data:Satisfactory short-term results have been observed after minimally invasive decompressive procedures, but intermediate-term and long-term outcomes have not been assessed. It is not yet clear whether decompressive laminectomy with concomitant fusion is the optimal surgical treatment for spinal stenosis combined with mild DS. We, therefore, evaluated minimum 3-year clinical outcomes and radiologic changes in patients with LSS and grade 1 DS, who underwent microsurgical bilateral decompression via a unilateral approach, without fusion. Methods:We assessed 21 consecutive patients who underwent surgery conducted by a single surgeon of our hospital, between 2005 and 2007. The Oswestry Disability Index was determined preoperatively, just before discharge, and at last follow-up. Plain dynamic x-rays were used to determine slip percentages. Results:Average patient age and clinical and radiologic follow-up periods were 67 years, 49.3 months, and 18 months, respectively. Preoperative, immediate postoperative, and last follow-up average Oswestry Disability Indices were 59.52±9.00, 50.19±7.23, and 26.19±12.42, respectively. However, 1 patient experienced aggravated symptoms and later underwent a fusion procedure. Of the 22 levels with spondylolisthesis, 15 had no sagittal motion as the difference in slip percentage on dynamic x-rays, but 7 showed sagittal motion. Average slip percentages increased from 13.90±5.41% to 14.60±5.78% for levels without sagittal motion on dynamic x-ray, and from 13.12±3.48% to 18.58±4.55% for levels with sagittal motion. Conclusions:Despite small case series with retrospective design and the absence of a control group, our study suggests that bilateral decompression via a unilateral approach in patients with LSS and grade 1 DS showed good mid-term clinical outcomes, despite an increase in slip percentage.However, more marked increases in slippage were observed in patients with sagittal motion in spondylolisthesis levels on preoperative dynamic x-ray, than in patients without sagittal motion. Therefore, bilateral decompression via a unilateral approach can aggravate symptoms related to instability in patients with preoperative sagittal motion on dynamic x-ray, and needs a longer term follow-up than in our study.

Long-term outcomes of 2 cervical laminoplasty methods: midline splitting versus unilateral single door.

Background: Two major current methods are midline splitting laminoplasty (MSL) and unilateral single-door laminoplasty (USDL). Few studies have compared the 2 techniques. Methods: We retrospectively analyzed the outcomes of 100 consecutive myelopathy patients who underwent decompressive laminoplasty between January 2004 and June 2008. The mean follow-up duration was 48.2 months. Results: The mean Japanese Orthopedic Association scores changed from 6.9 to 11.9 in the MSL group and from 6.2 to 12.4 in the USDL group, resulting in mean calculated recovery rates of 55.5% and 63.0%, respectively (P=0.14). Mean cervical lordosis declined from 12.0 to 10.2 degrees in the MSL group and from 10.3 to 8.5 degrees in the USDL group (P=0.24). Mean cervical range of motion declined from 27.8 to 25.6 degrees in the MSL group, and from 23.4 to 16.0 degrees in the USDL group (P=0.38). Bony spinal canal dimension increased from 201.2 to 280.8 mm2 in the MSL group and from 204.3 to 331.7 mm2 in the USDL group (P<0.001). In the USDL group, 6 patients experienced postoperative neck pain, 7 experienced C5 palsy, and 2 experienced cerebrospinal fluid leakage. No such complications occurred in the MSL group (P≥0.05 for both complications). Conclusions: MSL and USDL patients had similar long-term clinical and radiologic outcomes, except that bony canal expansion was greater in the latter. We believe that removal of the ligamentum flavum and drilling of the internal bony edge were factors in the favorable clinical outcomes and low rate of complications in the MSL group.

Reversible Aggravation of Neurological Deficits after Steroid Medication in Patients with Venous Congestive Myelopathy Caused by Spinal Arteriovenous Malformation

Steroids are empirically used to medicate patients with myelopathy of unknown etiology. We report the reversible aggravation of neurological status after steroid administration in a patient with venous congestive myelopathy (VCM). We retrospectively evaluated 36 patients with angio-graphically confirmed spinal arteriovenous malformation (SAVM) from a prospectively collected neurointerventional database. We evaluated steroid medication and neurological aggravation using Aminoff grading and analyzed using Fishers exact test whether steroid medication is related to neurological aggravation and spinal cord edema as demonstrated on MR T2-WI. Among 26 patients who had been treated with steroids, ten had aggravated neurological deficits. The aggravation in these ten patients was related to the steroid medication (P = 0.039 in all patients) and only marginally to VCM with spinal cord edema as seen on T2-WI (P = 0.074). Aggravation caused by using a high intravenous dose (250–1000 mg) of methylprednisolone or dexamethasone at 8–20 mg/day slowly decreased after stopping the steroid medication. Steroids were reversibly detrimental in patients with VCM caused by SAVM. A history of neurological aggravation after the use of steroids may suggest the diagnosis of SAVM associated with VCM.

Fatty Degeneration of Paraspinal Muscle in Patients With the Degenerative Lumbar Kyphosis: A New Evaluation Method of Quantitative Digital Analysis Using MRI and CT Scan.

Study Design:A comparative case-control study. Objective:The aim of this study was to quantify the degree of paraspinal muscle changes in degenerative lumbar kyphosis (DLK) patients using magnetic resonance imaging and computed tomography scanning. Summary of Background Data:Although the pathophysiology of DLK is not completely understood, extensive degeneration and weakness of the lumbar extensor muscles are thought to underlie the condition in most patients. However, there is no ideal method to quantify the degree of fat infiltration and atrophy of the paraspinal muscles in patients with DLK. Materials and Methods:The study group comprised 20 patients with DLK and 20 healthy volunteers. The cross-sectional areas of the psoas, erector spinae (ES), multifidus (MF), quadratus lumborum, and vertebral body were measured. The ratio between the cross-sectional area of the muscle and the vertebral body was used to evaluate lumbar muscularity. The degree of fatty change was evaluated by measuring the ratio between the mean signal intensity of the muscle and that of the subcutaneous fat within regions of interest. Results:Muscularity in the MF and ES was not significantly different between the DLK and control groups at L1, L2, or L3, but was significantly different at L4 (ES, P=0.001; MF, P=0.001) and L5 (ES, P=0.001; MF, P=0.015). The mean signal intensities of the ES and MF were higher in the DLK group than in the control group at all levels. The degree of fatty change in the ES and MF was significantly higher in the DLK group than in the control group (P<0.05). Conclusions:Quantitative analysis using magnetic resonance imaging and computed tomography scanning showed differences in paraspinal muscle volume and fatty degeneration between patients with DLK and healthy volunteers. This evaluation method may be useful for measuring the extent of paraspinal muscle degeneration.

Spinal pedicle subtraction osteotomy for fixed sagittal imbalance patients

In addressing spinal sagittal imbalance through a posterior approach, the surgeon now may choose from among a variety of osteotomy techniques. Posterior column osteotomies such as the facetectomy or Ponte or Smith-Petersen osteotomy provide the least correction, but can be used at multiple levels with minimal blood loss and a lower operative risk. Pedicle subtraction osteotomies provide nearly 3 times the per-level correction of Ponte/Smith-Petersen osteotomies; however, they carry increased technical demands, longer operative time, and greater blood loss and associated significant morbidity, including neurological injury. The literature focusing on pedicle subtraction osteotomy for fixed sagittal imbalance patients is reviewed. The long-term overall outcomes, surgical tips to reduce the complications and suggestions for their proper application are also provided.

MRI in presumed cervical anterior spinal artery territory infarcts

WE report the MRI findings in two patients with presumed cervical spinal cord infarcts in the anterior spinal artery territory. MRI revealed abnormal signal intensities and/or band-like enhancement in the anterior two-thirds of the cervical spinal cord, corresponding to the vascular territory of the anterior spinal artery. Clinically there was an anterior spinal cord syndrome.