Posterior Occipitocervical Fixation and Intrathecal Baclofen Therapy for the Treatment of Basilar Invagination with Klippel-Feil Syndrome: A Case Report.

Klippel-Feil syndrome (KFS) is characterized by the congenital fusion of the cervical vertebrae and is sometimes accompanied by anomalies in the craniocervical junction. In basilar invagination (BI), which is a dislocation of the dens in an upper direction, compression of the brainstem and cervical cord results in neurological defects and surgery is required. A 16-year-old boy diagnosed with KFS and severe BI presented with spastic tetraplegia, opisthotonus and dyspnea. CT scans showed basilar impression, occipitalization of C1 and fusion of C2/C3. MRI showed ventral compression of the medullocervical junction. Posterior occipitocervical reduction and fusion along with decompression were performed. Paralysis gradually improved postoperatively over 3 weeks. However, severe spasticity and opisthotonus persisted and intrathecal baclofen (ITB) therapy was initiated. Following this, opisthotonus disappeared and spasticity of the extremities improved. Rehabilitation therapy continued by controlling the dose of ITB. Five years after the surgery, self-propelled wheelchair driving was achieved and activities of daily life improved. The treatment strategy for patients with BI and congenital anomalies remains controversial. Posterior reduction and internal fixation using instrumentation were effective techniques in this case. Spasticity control achieved through a combination of surgery and ITB treatment enabled the amelioration of therapeutic efficacy of rehabilitation and the improvement of ADL.

One-Leg Robotic-Assisted Gait Training Efficiently Improves Gait Independence for Acute Stroke Hemiplegic Patients: A Prospective Pilot Study.

ABSTRACT: Welwalk is a one-leg robotic-assisted gait system for stroke hemiplegic patients. This study examined the feasibility and efficacy of gait training using Welwalk (Welwalk training) for hemiplegic patients in the early phase after stroke onset, via cooperation between acute care and rehabilitation hospitals. Seven acute stroke patients (mean number of days from onset = 7.9) with severe lower extremity paralysis participated. Patients underwent Welwalk training for 40 min/d, 5 d/wk in an acute care hospital, then 7 d/wk in a rehabilitation hospital with a seamless transition. Functional Independence Measure scores for walking were assessed weekly. The endpoint was reaching Functional Independence Measure walk score of 5 (supervision level). The primary outcome was improvement efficiency of Functional Independence Measure walk, which was the increase in Functional Independence Measure walk score divided by the number of weeks required. Functional Independence Measure walk score for all patients improved from 1.1 to 5 ( P = 0.01, r = 0.96). The mean number of weeks to achieve Functional Independence Measure walk score of 5 was 5 wks, and the improvement efficiency of Functional Independence Measure walk had a mean value of 0.9. No adverse events were reported during Welwalk training. Hemiparetic patients' gait independence may be safely and rapidly improved by starting Welwalk training in the early phase after stroke onset.

A cross-sectional survey of consistent rehabilitation through long-term care insurance in Japan: a questionnaire survey.

There seems to be a lack of consistency of maintenance/community-based rehabilitation through long-term care insurance. We aimed to clarify whether consistent rehabilitation can be performed through long-term care insurance by questionnaires. Materials and Methods: This study was a cross-sectional study in a nationwide survey among rehabilitation staff and care recipients who completed disease-specific rehabilitation and required maintenance/community-based rehabilitation through long-term care insurance. Consistency of rehabilitation was compared using Fisher's exact tests. The concordance of the rehabilitation evaluation and treatment conducted under medical and long-term care insurance was assessed using the κ coefficient. Results: Six hundred questionnaires from care recipients and staff were analyzed. Of the rehabilitation staff, 264 (44%) obtained rehabilitation plans from medical institutions. There was a significant difference between the responses of "referral from the same medical corporation" and "obtaining the rehabilitation plan" by Fisher's exact test (odds ratio: 3.242; P<0.001). Most rehabilitation treatments under medical insurance comprised walking or training with parallel rods/canes [498 patients (83%)], and 454 patients (76%) received stretching and range-of-motion training for the limbs and spine for long-term care insurance. Muscle strength evaluation was the most frequently conducted under medical and long-term care insurance [383 (73%) and 487 (83%), respectively]. The concordance of the evaluation and treatment content, except for disease-specific evaluation, was low (κ coefficient≤0.6). Conclusions: The rate of provision of rehabilitation plans was low, and evaluation and treatment content under medical and long-term care insurance was inconsistent. Our results draw attention to the need for consistent rehabilitation plans between disease-specific and maintenance/community-based rehabilitation.

Clinical outcomes after medial patellofemoral ligament reconstruction: an analysis of changes in the patellofemoral joint alignment.

PURPOSE: Medial patellofemoral ligament (MPFL) reconstruction using the hamstring tendon is widely performed to treat recurrent patellar dislocation. MPFL reconstruction includes a post-operative process of necrosis and reperfusion of the hamstring tendon graft. We hypothesise that the patella gradually shifts laterally because of this process, ultimately affecting the patellofemoral joint alignment. This study aimed to analyse the chronological changes in the patellofemoral joint alignment and the outcomes of MPFL reconstruction. METHODS: In this retrospective case-series study, the Knee Society, Lysholm, and Kujala scores were evaluated in 24 consecutive patients (27 knees). To evaluate patellar tracking defects, radiographic indices including the tilting angle, the lateral shift ratio, and the congruence angle were measured before, immediately after, and three, 12, and 36 months after MPFL reconstruction. RESULTS: Post-operative Kujala, Knee Society, and Lysholm scores for the study population significantly improved relative to the pre-operative scores. The tilting and congruence angles at three months after the operation significantly increased relative to those recorded immediately after the operation. The tilting and congruence angles were not significantly different at three, 12, and 36 months after the operation. CONCLUSIONS: The post-operative outcomes of MPFL reconstruction for recurrent patellar dislocation were favourable. Insufficient union between the bone tunnel and tendon graft, along with an elongation of the necrotic tendon graft, may change the alignment of the patellofemoral joint within three months after the operation. Therefore, we believe it is necessary to refrain from knee rotation that places lateral stress on the patella until three months after the operation.

Hepatocyte growth factor regulates HIF-1α-induced nucleus pulposus cell proliferation through MAPK-, PI3K/Akt-, and STAT3-mediated signaling.

Intervertebral discs are important for maintaining mobility and offer support to the body trunk. If these discs lose their biomechanical features, lower back pain can occur. We previously reported that hepatocyte growth factor (HGF) promotes cell proliferation and suppresses apoptosis, inflammation, and matrix degradation in nucleus pulposus (NP) cells. In the present study, we investigated the molecular mechanisms of how HGF promotes the proliferation of NP cells in hypoxic conditions. Hypoxic stimulation promoted modest cell proliferation, which was further upregulated by HGF. Expression of hypoxia-inducible factor (HIF-1α) protein, which contributes to the maintenance of homeostasis in NP cells, was also upregulated in hypoxia-treated cell groups; HGF further increased HIF-1α expression in NP cells. Additionally, knockdown of HIF-1α expression significantly reduced the proliferation of NP cells. An MAPK inhibitor inhibited the expression of HIF-1α and pERK, as well as cell proliferation in a dose-dependent manner. Similarly, inhibiting the PI3K/Akt and STAT3 pathways also decreased the expression of HIF-1α and cell proliferation. These results show that under hypoxic conditions, HGF promotes NP cell proliferation via HIF-1α-, MAPK-, PI3K/Akt-, and STAT3-mediated signaling which is involved in this pathway. The control of these signaling pathways may be a target for potential therapeutic strategies for the treatment of disc degeneration in hypoxic conditions.

Revascularization to the bone tunnel wall after anterior cruciate ligament reconstruction may relate to the distance from the vessels.

PURPOSE: We use magnetic resonance angiography to evaluate the difference of vascular ingrowth to the bone tunnel on the anterior and posterior walls quantitatively after anterior cruciate ligament reconstruction. MATERIALS AND METHODS: One hundred patients underwent anterior cruciate ligament reconstruction with multi-stranded semitendinosus tendons. They were retrospectively divided into those who underwent magnetic resonance angiography 2, 3, 4 to 6, and ≥ 7 months after surgery. The mean signal-to-noise ratios of the bone tunnel walls in the femur and tibia from the digital data were measured and compared for the anterior and posterior walls. RESULTS: The signal-to-noise ratio of the posterior wall of the femoral bone tunnel was significantly higher than that of the anterior wall in each group. On the tibial side, the signal-to-noise ratio of the anterior wall was significantly higher than that of the posterior wall at ≥4 months after surgery. CONCLUSIONS: This study showed that the blood flow after anterior cruciate ligament reconstruction to the femoral bone tunnel is maintained from the posterior wall, and is maintained to the tibial side from the anterior wall 4 months postoperatively. Revascularization to the bone tunnel wall after anterior cruciate ligament reconstruction may relate to the distance from the vessels.

Relationship of alignment in the lower extremity with early degeneration of articular cartilage after resection of the medial meniscus: Quantitative analysis using T2 mapping.

The objective of this study was to examine the relationship between cartilage degeneration early after partial medial meniscectomy and abnormal alignment in the lower extremity.The subjects were 34 patients (37 knees) with medial meniscal tear who underwent arthroscopic partial meniscectomy. MRI was performed before and 6 months after surgery. T2 mapping images in sagittal sections of medial femoral condyle were produced and 10 regions of interest were set at intervals of 10° in the articular cartilage in the femur. Subjects with an increase in T2 of ≥6% at a flexion angle of 30° were assigned to the degeneration group. Patient background, hip-knee-ankle (HKA) angle, and total resection of meniscal segments were compared between this group and the other patients to identify factors involved in degeneration of articular cartilage.T2 values 6 months after surgery in 3 ROIs at flexion angles of 30° to 50° were significantly longer than those before surgery. The preoperative HKA angle was significantly higher in the degeneration group. T2 values in articular cartilage of the femoral condyle increased earlier after meniscectomy with abnormal alignment in the lower extremity.Meniscectomy in cases with abnormal alignment may have a risk of early onset of osteoarthritis.Level of evidence: Level IV.

A modified Terrono classification for Type 1 thumb deformity in rheumatoid arthritis: a cross-sectional analysis.

The most common thumb deformity in rheumatoid arthritis is Nalebuff Type 1 deformity (boutonniere deformity). Type 1 deformity severely impairs hand function, and this impairment is evaluated by the Terrono classification. In some cases, the Terrono classification incorrectly categorizes advanced thumb deformity into earlier stages. We modified the Terrono classification by assessing the active range of motion of the interphalangeal joint prior to assessing the passive range of movement of the metacarpophalangeal joint. An active range of movement of the interphalangeal joint was strongly correlated with hand function. In 55 hands that we treated between 2004 and 2015, we compared the modified classification with the original Terrono classification. Our modified classification could detect advanced deformity earlier, and was more strongly correlated with hand function. Additionally, correlation analysis showed that advanced Type 1 deformity should be treated first, even in cases with severe ulnar drift. Our results suggest that the modified classification may benefit the treatment of Type 1 deformity, including joint-preserving surgery. Level of evidence: III.

Treadmill Running in Established Phase Arthritis Inhibits Joint Destruction in Rat Rheumatoid Arthritis Models.

Exercise therapy inhibits joint destruction by suppressing pro-inflammatory cytokines. The efficacy of pharmacotherapy for rheumatoid arthritis differs depending on the phase of the disease, but that of exercise therapy for each phase is unknown. We assessed the differences in the efficacy of treadmill running on rheumatoid arthritis at various phases, using rat rheumatoid arthritis models. Rats with collagen-induced arthritis were used as rheumatoid arthritis models, and the phase after immunization was divided as pre-arthritis and established phases. Histologically, the groups with forced treadmill running in the established phase had significantly inhibited joint destruction compared with the other groups. The group with forced treadmill running in only the established phase had significantly better bone morphometry and reduced expression of connexin 43 and tumor necrosis factor α in the synovial membranes compared with the no treadmill group. Furthermore, few cells were positive for cathepsin K immunostaining in the groups with forced treadmill running in the established phase. Our results suggest that the efficacy of exercise therapy may differ depending on rheumatoid arthritis disease activity. Active exercise during phases of decreased disease activity may effectively inhibit arthritis and joint destruction.

Clinical Outcome of Muscle-Preserving Interlaminar Decompression (MILD) for Lumbar Spinal Canal Stenosis: Minimum 5-Year Follow-Up Study.

INTRODUCTION: Favorable short-term outcomes have been reported following muscle-preserving interlaminar decompression (MILD), a less invasive decompression surgery for lumbar spinal canal stenosis (LSCS). However, there are no reports of mid- to long-term outcomes. The purpose of this study was to evaluate the clinical outcomes five or more years after treatment of LSCS with MILD. METHODS: Subjects were 84 cases with LSCS (44 males; mean age, 68.7 years) examined five or more years after MILD. All patients had leg pain symptoms, with claudication and/or radicular pain. The patients were divided into three groups depending on the spinal deformity: 44 cases were without deformity (N group); 20 had degenerative spondylolisthesis (DS group); and 20 had degenerative scoliosis (DLS group). The clinical evaluation was performed using Japanese Orthopedic Association (JOA) scores, and revision surgeries were examined. Changes in lumbar alignment and stability were evaluated using plain radiographs. RESULTS: The overall JOA score recovery rate was 65.5% at final follow-up. The recovery rate was 69.5% in the N group, 65.2% in the DS group, and 54.0% in the DLS group, with the rate of the DLS group being significantly lower. There were 16 revision surgery cases (19.0%): seven in the N group (15.9%), three in the DS group (15.0%) and six in the DLS group (30.0%). There were no significant differences between pre- and postoperative total lumbar alignment or dynamic intervertebral angle in any of the groups, slip percentage in the DS group, or Cobb angle in the DLS group. CONCLUSIONS: The mid-term clinical results of MILD were satisfactory, including in cases with deformity, and there was no major impact on radiologic lumbar alignment or stability. The clinical outcomes of cases with degenerative scoliosis were significantly less favorable and the revision rate was high. This should be taken into consideration when deciding on the surgical procedure.

Leg Muscle Strength After Lateral Interbody Fusion Surgery Recovers Over Time After Temporary Muscle Weakness.

STUDY DESIGN: Case-control study. OBJECTIVE: The objective of this study was to reveal the changes of leg muscle strength after lateral interbody fusion (LIF). SUMMARY OF BACKGROUND DATA: Muscle trauma and damage to intermuscular nerves due to dissection of the psoas are recognized perioperative complications of LIF. Although reduced leg strength is temporary in many cases, the underlying changes have not been studied in detail. METHODS: Leg muscle strength was measured quantitatively before LIF surgery and 1 week, 2 weeks, 3 weeks, 4 weeks, 8 weeks, and 12 weeks after surgery (n=38). Reduced muscle strength was defined as <80% of the preoperative measurement. The psoas position (PP%) was calculated from axial T2-weighted magnetic resonance images and compared with the degree of psoas and quadriceps muscle strength reduction at 1 week after surgery on the approach side. Twenty cases that underwent a posterior lumbar approach (posterior group) acted as controls. RESULTS: The proportion of patients with reduced psoas muscle strength 1 week after LIF was 60.5% on the approach side and 39.5% on the healthy side, versus 30.0% in the posterior group. The corresponding results for the quadriceps were 34.2%, 39.5%, and 25.0%, respectively. All cases had strength improvement on the approach side by 12 weeks postsurgery in the psoas and by 4 weeks postsurgery for the quadriceps. Psoas muscle strength and quadriceps strength at 1 week after surgery were correlated (ρ=0.57, P<0.001). There was a low inverse correlation between PP% and quadriceps strength at 1 week (ρ=-0.31, P<0.001). CONCLUSIONS: Muscle strength declined in both the psoas and quadriceps muscle groups after LIF; however, the effect was temporary and strength recovered over time. Reduced postoperative quadriceps muscle strength may relate the position of the psoas muscle via increased irritation of the lumbar plexus during the splitting maneuver.

Facet Joint Osteoarthritis Affects Spinal Segmental Motion in Degenerative Spondylolisthesis.

STUDY DESIGN: This is a retrospective clinical case series (case-control study). OBJECTIVE: To clarify the influence of facet joint osteoarthritis (FJOA) on the pathology of degenerative spondylolisthesis (DS) using in vivo 3-dimensional image analysis. SUMMARY OF BACKGROUND DATA: There are no radical treatments to prevent progression of DS in patients with lumbar spinal canal stenosis associated with DS. Therefore, an effective treatment method based on the pathology of DS should be developed. PATIENTS AND METHODS: In total, 50 patients with lumbar spinal canal stenosis involving L4/5 who underwent dynamic computed tomography were divided into 2 groups: with DS [spondylolisthesis (Sp) group; 12 male, 14 female; mean age, 74 y]; and without DS (non-Sp group; 15 male, 9 female; mean age, 70 y). Degeneration of the intervertebral disk and FJOA at L4/5 were evaluated using magnetic resonance imaging. Disk and intervertebral foramen heights, the distance between the craniocaudal edges of the facet joint, and the interspinous distance were measured on dynamic computed tomographic images. Also, in vivo 3-dimensional segmental motion was evaluated using the volume merge method. RESULTS: There were no significant differences in degenerative findings for the intervertebral disk; however, progressive FJOA was detected in the Sp group. Dynamic changes in the distance between the craniocaudal edges of the facet joints were significantly larger in the Sp group. CONCLUSIONS: In this study, progressive FJOA and larger segmental motion in the distance between the craniocaudal edges of the facet joints were found in the Sp group. We clarified for the first time that DS involves ligament laxity due to FJOA that affects spinal segmental motion in vivo. We consider that a treatment method based on FJOA would be useful for treating patients with DS. LEVEL OF EVIDENCE: Level IV.

Osteoporotic effect on bone repair in lumbar vertebral body defects in a rat model.

INTRODUCTION: The number of patients who suffered from osteoporotic vertebral fractures is increasing. Osteoporosis has been reported to affect the healing process using long bone models. However, few studies have reported using vertebrae. In this study, we created a bone defect in the anterior part of vertebral body in ovariectomized rat and evaluated the healing process. METHODS: Fifty-six 12-week old Sprague Dawley rats were divided into ovariectomy (OVX) and sham operation groups. A bone defect was created in the vertebral body 8 weeks after the first surgery. In both groups, the vertebral bodies were harvested immediately or at 4, 8, or 12 weeks after the second surgery ( n = 7 at each time point). Bone volume (BV, mm3), bone volume fraction (BV/TV, %), trabecular thickness (Tb.Th, mm), trabecular number (Tb.N, 1/mm), and trabecular separation (Tb.Sp, µm) were evaluated by micro-computed tomography to assess the new bone formation. Histological analysis was also performed. RESULTS: The BV and the BV/TV were significantly lower at 4 and 12 weeks in the OVX group compared with those in the sham group. The Tb.Th was significantly lower at 8 and 12 weeks in the OVX group. Histologically, at 12 weeks, in the OVX group, the bone had a thinner, layered structure on the surface of the defect, and the trabecular structure was less dense. CONCLUSION: This study demonstrated that bone mass formation was suppressed and the quality of repaired bone was poor in the healing process of vertebral body defect under osteoporotic conditions. These findings could be the key to understand the pathology of osteoporotic vertebral fracture and to develop its therapies.

Effect of three-dimensional rotational deformity correction in surgery for adult degenerative scoliosis using lumbar lateral interbody fusion and posterior pedicle screw fixation.

INTRODUCTION: Corrective surgery for adult degenerative scoliosis using lateral interbody fusion (LIF) and additional posterior fixation is an efficient procedure. However, it is unclear how this procedure affects rotational deformity correction. Therefore, the goal of the present study was to use three-dimensional (3D) images, taken during surgery, to investigate rotational deformity correction in the treatment of adult degenerative scoliosis using LIF and posterior fixation using a pedicle screw system. METHODS: The subjects were 12 females who were treated using LIF and posterior fixation for adult degenerative scoliosis. The patients had a mean age of 72 (65-76) years. 3D images were acquired before surgery, after LIF, and after additional posterior fixation. Rotational angles of the upper vertebra with respect to the lower vertebra of each fixed segment were measured in 3 planes. Correction factors for rotational deformity were investigated after LIF and additional posterior fixation. RESULTS: There were significant improvements in radiographical parameters for global spinal balance. The correction angles per segment were 4.7° for lateral bending, 6.9° for lordosis, and 4.5° for axial rotation. LIF was responsible for correction of four-fifths of lateral bending and axial rotation, and two-thirds of lordotic changes. CONCLUSIONS: Lateral bending, axial rotational deformities, and lordosis were primarily corrected by LIF. Further lordosis correction was achieved using additional posterior fixation. These results indicate that corrective surgery for adult degenerative scoliosis using these procedures is effective for rotational deformity correction and leads to an ideal global spinal alignment.

Bone Regeneration of Osteoporotic Vertebral Body Defects Using Platelet-Rich Plasma and Gelatin ß-Tricalcium Phosphate Sponges.

The objective of the present study was to investigate the effect of platelet-rich plasma (PRP) combined with gelatin ß-tricalcium phosphate (ß-TCP) sponge on bone generation in a lumbar vertebral body defect of ovariectomized rat. After creating critical-size defects in the center of the anterior vertebral body, the defects were filled with the following materials: (1) no material (control group), (2) gelatin ß-TCP sponge with PRP (PRP sponge group), and (3) gelatin ß-TCP sponge with phosphate-buffered saline (PBS sponge group). Microcomputed tomography and histological evaluation were performed immediately after surgery and at 4, 8, and 12 weeks to assess bone regeneration. Biomechanical test was also performed at postoperative week 12. In the PRP sponge group, both imaging and histological examination showed that visible osteogenesis was first induced and additional growth of bone tissue was observed in the transplanted sponge, compared with the PBS sponge group. There was no negative effect of either PRP sponge or PBS sponge transplantation on bone tissue generation around the periphery of the defect. Biomechanical test showed increased stiffness of the affected vertebral bodies in the PRP sponge group. These results indicate that PRP-impregnated gelatin ß-TCP sponge is effective for facilitating bone regeneration in lumbar vertebral bone defect under osteoporotic condition. PRP combined with gelatin ß-TCP sponges could be potentially useful for developing a new approach to vertebroplasty for osteoporotic vertebral fracture.

Changes in Basic Movement Ability and Activities of Daily Living After Hip Fractures: Correlation Between Basic Movement Scale and Motor-Functional Independence Measure Scores.

OBJECTIVE: The aim of this study was to examine the correlation between basic movement ability and activities of daily living (ADL) in elderly patients after hip fracture surgery and predict ADL outcomes from changes in basic movement ability. DESIGN: Fifty-four patients receiving rehabilitation after hip fracture surgery were collected prospectively. Ambulatory ability was evaluated using a Basic Movement Scale (BMS), and ADL was evaluated using the motor subscale of the Functional Independence Measure (motor-FIM). From the results of evaluating BMS and motor-FIM weekly, the important postoperative period to regain ADL was investigated. RESULTS: There was a close correlation between BMS and motor-FIM scores at each evaluation point (r = 0.971, P < 0.001) and a significant correlation between weekly BMS and motor-FIM gains (r = 0.741, P < 0.001). Cluster analysis of BMS scores from postoperative week (POW) 2 to 12 showed three patterns of change, with BMS scores at POW 2 reflecting the outcome. CONCLUSIONS: The very strong correlation between BMS and motor-FIM scores suggests that BMS is a favorable indicator of changes in ADL. Because basic movement ability at POW 2 also reflected the prognosis, constructive interventions should be implemented early to help patients ambulate and regain other basic movements by no later than POW 2.

Magnetic Resonance Imaging Evaluation of the Effects of Surgical Invasiveness on Paravertebral Muscles After Muscle-preserving Interlaminar Decompression (MILD).

STUDY DESIGN: This is a retrospective study. OBJECTIVES: The aim of this study was to determine the extent of damage to the paravertebral muscles after muscle-preserving interlaminar decompression (MILD) using magnetic resonance imaging to evaluate changes in the multifidus muscle (MF). SUMMARY OF BACKGROUND DATA: Short-term surgical outcomes of MILD for lumbar spinal canal stenosis (LSCS) are satisfactory; however, the extent of damage to the paravertebral muscles after MILD remains unclear. METHODS: Thirty-four patients (18 men/16 women; mean age: 72.6 y) who had LSCS treated with MILD were retrospectively investigated. A total of 61 decompressed disk levels [L2/3(5); L3/4(21); L4/5(30); L5/S(5)] and 34 nondecompressed levels (L1/2) were assessed. There was 1 decompressed disk level in 12 cases, 2 in 17 cases, and 3 in 5 cases. Magnetic resonance imaging scans were obtained before surgery and at 3 and 12-18 months after surgery, using the same scanner. The rate of paravertebral muscle atrophy was evaluated to compare the area of the MF in the T2-weighted axial plane (intervertebral disk level) preoperatively and postoperatively, using OsiriX Medical Imaging Software. Changes in muscle signal intensity were also recorded. Statistical analysis was performed using 3-way analysis of variance with the post hoc Fisher PSLD test. RESULTS: The rate of MF atrophy was 4.0% at the decompressed levels and 2.1% at the nondecompressed levels. There were no changes of signal intensity in the MF between the preoperative and postoperative periods. In decompressed levels, muscle atrophy and signal intensity were significantly improved from 3 months to 12-18 months after surgery. The number and level of the decompressed disks did not affect the extent of muscle injury. CONCLUSIONS: The extent of paravertebral muscle injury after MILD is satisfactory. The midline interlaminar approach used in this technique may prevent local denervation and irreversible damage to the paravertebral muscles. These results indicate that MILD is useful to treat LSCS less invasively.

Innovative Technique for the Placement of the Drainage Tube for Microendoscopic Spinal Decompression.

STUDY DESIGN: A technical note and retrospective study. OBJECTIVES: The objectives were to describe a new method of drainage tube placement during microendoscopic spinal decompression, and compare the positioning and fluid discharge obtained with this method and the conventional method. SUMMARY OF BACKGROUND DATA: To prevent postoperative epidural hematoma after microendoscopic decompression, a drainage tube must be placed in a suitable location. However, the narrow operative field makes precise control of the position of the tube technically difficult. We developed a method to reliably place the tube in the desired location. MATERIALS AND METHODS: We use a Deschamps aneurysm needle with a slightly curved tip, which we call a drain passer. With the microendoscope in position, the drain passer, with a silk thread passed through the eye at the needle tip, is inserted percutaneously into the endoscopic field of view. The drainage tube is passed through the loop of silk thread protruding from the inside of the tubular retractor, and the thread is pulled to the outside, guiding the end of the drainage tube into the wound. This method was used in 23 cases at 44 intervertebral levels (drain passer group), and the conventional method in 20 cases at 32 intervertebral levels (conventional group). Postoperative plain radiographs were taken, and the amount of fluid discharge at postoperative hour 24 was measured. RESULTS: Drainage tube positioning was favorable at 43 intervertebral levels (97.7%) in the drain passer group and 26 intervertebral levels (81.3%) in the conventional group. Mean fluid discharge was 58.4±32.2 g in the drain passer group and 38.4±23.0 g in the conventional group. Positioning was significantly better and fluid discharge was significantly greater in the drain passer group. CONCLUSION: The results indicate that this method is a useful drainage tube placement technique for preventing postoperative epidural hematoma.

A New Method of Measuring the Occipitocervical Angle That Could be Applied as an Intraoperative Indicator During Occipitocervical Fusion.

STUDY DESIGN: A method for measuring occipitocervical angle. OBJECTIVE: To develop a new method of measurement for assessing the occipitocervical angle using intraoperative fluoroscopic imaging, and to examine its reliability. SUMMARY OF BACKGROUND DATA: To avoid postoperative complications following occipitocervical fusion, it is vital to obtain a suitable fusion angle between the occipital bone and the upper cervical spine. MATERIALS AND METHODS: The subjects were 30 cases with occipito-atlanto-axial lesions and 30 healthy volunteers. Lateral plain radiographs of the cervical spine in neutral position were used to draw the McGregor line, the line between the external occipital protuberance and the most caudal point on the midline occipital curve (Oc line), the tangential line of the inferior endplate of the C2 vertebra (C2 line), and the posterior longitudinal line of the C2 vertebra (Ax line). The angles formed by these 4 lines and the horizontal line were measured. The O-C2 angle and the Oc-Ax angle, the new indicator, were measured by 3 doctors and reliability was evaluated. RESULTS: In the disease group, mean intraobserver variances of the McGregor, Oc, C2, Ax, O-C2, and Oc-Ax angles were 0.7, 1.3, 1.5, 1.2, 1.6, and 1.9 degrees. Mean intraobserver intraclass correlation coefficients were 0.997, 0.994, 0.994, 0.997, 0.989, and 0.988, showing high intraobserver reliability for all angles. Mean interobserver intraclass correlation coefficients were 0.998, 0.996, 0.994, 0.997, 0.988, and 0.990, showing high interobserver reliability for all angles. The same reliability was obtained in the healthy group. CONCLUSIONS: The Oc-Ax angle is as reliable an indicator as the conventional O-C2 angle, and could be used as a new intraoperative indicator for occipitocervical fusion. It may be particularly useful in cases where it is difficult to identify the McGregor line and/or the inferior endplate of the C2 vertebra. LEVEL OF EVIDENCE: Level 3-diagnostic study.

Dislodgement and gastrointestinal tract penetration of bone cement used for spinal reconstruction after lumbosacral vertebral tumor excision: A case report.

INTRODUCTION: Polymethylmethacrylate (PMMA) cement is useful for spinal reconstruction, but can cause complications including new vertebral fractures, neurological disorders and pulmonary embolism. We report a case in PMMA cement used for spinal reconstruction after tumor curettage dislodged and penetrated the gastrointestinal tract. DIAGNOSES: The patient was diagnosed with a retroperitoneal extragonadal germ cell tumor at age 27 years. After chemotherapy and tumor resection, the tumor remained. It gradually increased in size and infiltrated lumbosacral vertebrae, causing him to present at age 35 years with increased low back pain. Image findings showed bone destruction in the vertebral bodies accompanied by neoplastic lesions. The left and right common iliac arteries and inferior vena cava were enclosed in the tumor on the anterior side of the vertebral bodies. Lumbosacral bone tumor due to direct extragonadal germ cell tumor infiltration was diagnosed. A 2-step operation was planned; first, fixation of the posterior side of the vertebral bodies, followed by tumor resection using an anterior transperitoneal approach, and spinal reconstruction using PMMA cement. After surgery, the PMMA cement gradually dislodged towards the anterior side and, 2 years 9 months after surgery, it had penetrated the retroperitoneum. The patient subsequently developed nausea and abdominal pain and was readmitted to hospital. The diagnosis was intestinal blockage with dislodged PMMA cement, and an operation was performed to remove the cement present in the small intestine. There was strong intra-abdominal adhesion, the peritoneum between the vertebral bodies and intestine could not be identified, and no additional treatment for vertebral body defects could be performed. After surgery, gastrointestinal symptoms resolved. CONCLUSION: Although this was a rare case, when using bone cement for vertebral body reconstruction, the way of anchoring for the cement must be thoroughly planned to assure no cement dislodgement can occur.