Cutaneous nontuberculous mycobacterial infections in Japan: Review of the Japanese literature.

Nontuberculous mycobacteria cause a wide range of infections, including cutaneous infections, in both immunocompromised and immunocompetent patients. Although pulmonary nontuberculous mycobacterial infections have increased significantly in Japan in recent years, there is less evidence on clinical and microbiological characteristics of cutaneous nontuberculous mycobacterial infections in Japan. We reviewed 86 Japanese cases reported between July 2016 and November 2021 and analyzed them in conjunction with the eight patients from our institution who were diagnosed with cutaneous nontuberculous mycobacterial infections by culture between 2015 and 2021. In the aggregate series, the average patient age was 60 years, and the ratio of immunocompromised hosts was 53%, both of which were higher than those in previous reports from other countries. No female predominance was observed, unlike in pulmonary nontuberculous mycobacteria infections. Rapidly growing mycobacteria accounted for 58% of the cases (n = 54), whereas slowly growing mycobacteria for 43% (n = 40). Mycobacterium marinum (also known as Mycobacteroides marinum) (n = 20, 21%) was the most common cause, followed by Mycobacterium chelonae (n = 18, 19%), Mycobacterium abscessus (also known as Mycobacteroides abscessus) (n = 15, 16%), and Mycobacterium ulcerans (n = 11, 12%). While clinical appearance was variable, M ulcerans infections usually presented with ulcers, while nodules were common among infections caused by M chelonae and M marinum. Disseminated infections involving multiple organs were observed in 23 patients (24%). Thirty-two cases (30%) were preceded by exposure, including raising or handling fish, trauma, and invasive medical procedures. Most patients were treated with more than two antibiotics and responded to therapy.

High incidence of venous thromboembolism after acute cervical spinal cord injury in patients with ossification of the posterior longitudinal ligament.

Objective: To determine the incidence of venous thromboembolism (VTE) in patients with acute cervical spinal cord injury (SCI) and ossification of the posterior longitudinal ligament (OPLL).Design: Prospective cohort study.Setting: A department of a university hospital in Japan.Participants: This study included 57 patients (OPLL, n = 10; non-OPLL, n = 47) treated for acute cervical SCI between January 2011 and April 2017. Patients were classified according to motor complete paralysis (MC), motor incomplete paralysis (MIC), or normal motor function, based on American Spinal Injury Association (ASIA) Impairment Scale results.Interventions: N/A.Outcome Measures: All patients were screened for VTE by D-dimer monitoring, and some underwent ultrasonography. If ultrasonography indicated deep venous thrombosis (DVT) or if the D-dimers increased to ≥10 µg/mL, patients underwent contrast venography to detect VTE, including DVT or pulmonary embolism. We compared blood coagulability and VTE incidence in the OPLL and non-OPLL groups.Results: VTE occurred in 11 (19.3%) of 57 patients. The incidence of VTE was higher in the OPLL group than in the non-OPLL group (50% vs. 12.8%; P = 0.017) and higher in the MC group (57.1%) than in the MIC (8.3%; P = 0.002) or normal group (5.3%; P = 0.002). In the MC group, VTE occurred in 50% of OPLL patients and in 62.5% of non-OPLL patients (P = 0.529). In the MIC group, VTE occurred in 50% of OPLL patients and in none of the non-OPLL patients (P = 0.022).Conclusions: Patients with OPLL tended to develop VTE after SCI with motor complete and incomplete paralysis.

Association between intra-operative hemodynamic changes and corrective procedures during posterior spinal fusion in adolescent patients with scoliosis: A case-control study.

ABSTRACT: Previous reports indicated that a decrease in intra-operative cardiac output and mean arterial pressure occurs due to thoracic cage deformities when patients with scoliosis are placed in the prone position. The aims of this study were to investigate the occurrence of hypotension during posterior spinal fusion in adolescent patients with scoliosis, and the association between hypotension, surgical procedures, changes of thoracic cage morphology.This retrospective, single-center, case-control study included 106 patients who underwent surgeries for spinal deformity at our institute between June 2014 and March 2020. The inclusion criteria were: age ≤19 years at the time of surgery, lowest instrumented vertebra over L5, posterior spinal fusion as the first surgery for scoliosis, and no severe cardiac or pulmonary disease pre-operatively. Finally, 49 patients met the criteria, and were divided to 3 groups as follows: thoracic constructive curve using a 6.0-mm cobalt-chromium alloy circular rod (T-C group; n = 28); thoracolumbar/lumbar constructive curve using a 6.0-mm cobalt-chromium alloy circular rod (L-C group; n = 8); and thoracic constructive curve using a 5.5-mm cobalt-chromium alloy beam-like rod (T-B group; n = 13). The beam-like rod is characteristic as the rod is mounted to screw heads without cantilever force. Intra-operative changes in circulation associated with corrective procedures, perioperative data, and sagittal depth and sternum deviation of thoracic cage were compared between the 3 groups.The T-C group had a higher rate of hypotension alarm than did the other groups (7 vs 0 vs 0; P = .047). Corrective procedures included rodding 4 times, rod rotation maneuver once, and direct vertebral rotation twice. Blood pressure was increased by pausing the correction procedures, increasing infusion, and administering vasopressors. The T-C and T-B groups had greater sternum deviation parameters than the L-C group, both before and after surgery. All parameters associated with sagittal depth and sternum deviation decreased significantly after surgery in the T-C and the T-B groups.In corrective surgery for constructive thoracic scoliosis, the corrective procedures requiring the application of compression force in the forward direction should be closely monitored in view of their possible influence on circulatory conditions.

Association between mild cognitive impairment and lumbar degenerative disease in a Japanese community: A cross-sectional study.

Lumbar degenerative disease and dementia are increasing in super-aging societies and are both related to physical dysfunction and pain. However, the relationship between these diseases remains unclear. This cross-sectional study aimed to investigate the comorbidity rates of lumbar spinal canal stenosis (LSS) and mild cognitive impairment (MCI) and clarify the association between LSS presence, lumbar symptoms, and quality of life (QOL) related to low back pain and cognitive impairment in the Japanese population. We enrolled 336 participants (men 124; women 212; mean age 72.2 years) from a medical checkup program. LSS was diagnosed using a self-administered questionnaire, and lumbar symptoms were evaluated using the visual analog scale (low back pain, and pain and numbness of the lower limb). QOL related to low back pain was evaluated using the Japanese Orthopedic Association Back-Pain Evaluation Questionnaire (JOABPEQ: pain, and lumbar, and gait function). Radiological lumbar degeneration was classified using Kellgren-Lawrence grading and lateral radiographs of the lumbar spine. Cognitive function was measured using the Mini Mental State Examination (MMSE), and MCI was defined by a summary score of MMSE ≤27. Logistic and multiple linear regression analyses were performed to analyze the association between MCI, summary score of MMSE, and lumbar degenerative disease. The comorbidity rate of MCI and LSS was 2.1%, and the rate of MCI was 41% in participants with LSS. Lumbar function in JOABPEQ was associated with MCI. The presence of LSS and lumbar function in JOABPEQ were associated with MMSE. Over one-third of the people with LSS had MCI. The presence of LSS and deterioration of QOL due to low back pain were related to cognitive impairment. We recommend evaluating cognitive function for patients with LSS because the rate of MCI was high in LSS participants.

Flexional distance index: A new prognostic indicator of neurological outcomes at 4 years after cervical laminoplasty for K-line (+) ossification of the posterior longitudinal ligament.

OBJECTIVE: We aimed to investigate whether K-line in the neck flexion (FK-line), flexion angle (FA), or flexion distance index (FDI) could predict the recovery rate of the Japanese Orthopedic Association score (RR-JOA) at 4 years after cervical laminoplasty (LP) for ossification of the posterior longitudinal ligament (OPLL). METHODS: A new index, i.e., the FDI, which is based on the degree of neck flexion and the OPLL size on a lateral radiograph. "Flexional distance" is the distance from C2 to C7 in neck flexion, and "distance to OPLL" is the maximal distance from the line of the flexional distance to OPLL. FDI was defined as follows: FDI = flexional distance/distance to OPLL. Twenty-three patients with K-line (+) OPLL were evaluated at 4 years after LP (follow-up rate, 92%). We investigated the relationships between preoperative radiological factors, including FK-line, FA, and FDI, and RR-JOA at 4 years postoperatively. RESULTS: Preoperative FK-line and FA were significantly related with the RR-JOA at 1 year postoperatively, but not at 4 years postoperatively. Preoperative FDI was significantly positively correlated with the RR-JOA at 1 year and 4 years postoperatively (P = 0.0132, r = 0.504 and P = 0.0183, r = 0.484, respectively). Preoperative FDI < 2.5 was associated with worsening of the RR-JOA at 4 years postoperatively, with a probability of 80% DISCUSSIONS: FDI could predict the RR-JOA at 4 years after LP for OPLL. Decompression with fusion may be recommended for patients with preoperative FDI < 2.5. LEVEL OF EVIDENCE: 4.

Modified K-Line in Neck Extension Is a Prognostic Indicator of the Surgical Outcome at 5 Years After Cervical Laminoplasty for Cervical Spondylotic Myelopathy.

STUDY DESIGN: A retrospective comparison of the surgical outcome after cervical laminoplasty for cervical spondylotic myelopathy (CSM) using a modified K-line based on lordosis in neck extension as a predictor: in K-line Back CSM (KB group), the K-line crosses the ventral edge of any of the spinous processes, whereas in K-line Front CSM (KF group), the K-line does not. OBJECTIVE: To investigate the neurological and radiological outcomes 5 years after surgery and the contact between the spinal cord and posterior elements after laminoplasty for CSM using the modified K-line. SUMMARY OF BACKGROUND DATA: No indicators on a lateral radiograph can predict the neurological outcome after laminoplasty for CSM. METHODS: Patients with CSM were divided into KB (n = 20) and KF groups (n = 13). We compared the postoperative Japanese Orthopedic Association (JOA) score, recovery rate, grip-and-release and foot-tapping test results, alignment, and contact between the spinal cord and posterior elements between the two groups. RESULTS: The postoperative JOA score and its recovery rate were significantly lower in the KB group (12.4 points and 34.1%, respectively) than in the KF group (14.1 points and 59.0%, respectively) at final follow-up (P = 0.0415 and 0.0458). The grip-and-release and foot-tapping test results improved significantly in the KF group but not in the KB group. In the KB group, a larger lordotic angle in extension at 1 year postoperatively continued until final follow-up. The rate of recovery of the JOA score in patients with contacts at both C4/5 and C5/6 and any contact in the KB group (-1.5% and 31.9%, respectively) were lower (P = 0.0013 and 0.0534, respectively) than those in the KF group (58.6% and 60.7%, respectively). CONCLUSION: The K-line Back predicts a poor neurological outcome after laminoplasty for CSM. Decompression with fusion may be recommended for these patients.Level of Evidence: 4.

The effect of low back pain and neck-shoulder stiffness on health-related quality of life: a cross-sectional population-based study.

BACKGROUND: This cross-sectional study sought to determine the neck-shoulder stiffness/low back pain (NSS/LBP) comorbidity rate in a Japanese community population and to compare the quality of life (QOL) in individuals with comorbid NSS/LBP, asymptomatic individuals, and those with symptoms of NSS or LBP alone. METHODS: The sample included 1122 subjects (426 men; 696 women) with NSS and LBP symptoms in the previous 3 months, and were grouped according to NSS, LBP, comorbid NSS and LBP symptoms (Comorbid), or no symptoms (NP). They completed the MOS 36-Item Short-Form Health Survey (SF-36). Health QOL was evaluated by the eight domain scores and the Physical Component Summary (PCS) and Mental Component Summary (MCS) scores after adjusting for age. The primary outcome was to examine the association between NSS/LBP, NSS, or LBP and bodily pain of the eight domains of SF-36. Secondary outcome was to compare health-related QOL among the four groups. RESULTS: Morbidity was 45.6% for NSS and 51.9% for LBP. Comorbidity affected 23% of men and 33% of women. Comorbid NSS/LBP, NSS, and LBP alone were independently associated with bodily pain after adjusting for potential confounders. Men who exhibited comorbidity had significantly lower MCS scores than asymptomatic men. Women who exhibited comorbidity and LBP had significantly lower MCS scores than those with no symptoms or NSS alone. Women who exhibited comorbidity had significantly lower MCS scores than those with no symptoms or LBP alone. CONCLUSIONS: Comorbidity of the two diseases is prevalent in 23% of the men and 33% of women in the Japanese sample. Although NSS, LBP, and comorbidity were independently associated with QOL in terms of pain, QOL was worse in individuals who exhibited comorbidity than in those without symptoms or with NSS alone.

Coagulation, Vascular Morphology, and Vasculogenesis in Spinal Ligament Ossification Model Mice.

STUDY DESIGN: In vivo studies of the vascular system in ossification of the posterior longitudinal ligament (OPLL) model mice. OBJECTIVE: The aim of this study was to investigate blood coagulability, vascular morphology, and vasculogenesis capability, known as venous thromboembolism (VTE) risk factors in the ossification model, tiptoe walking (ttw) mice. SUMMARY OF BACKGROUND DATA: Patients with OPLL are more likely to develop VTE after spinal cord injury. Capillary mesh invasion of spinal ligaments precedes spinal ligament ossification in ttw mice. Investigation on vascular systems of ttw mice may contribute to clarifying its pathology. METHODS: Coagulability of blood samples from ttw and C57BL/6 (WT) mice were evaluated at 8, 16, and 24 weeks of age. Vascular morphology was assessed from a Hematoxylin-Eosin stained section by measuring vessel area. A tube formation assay was performed with endothelial cells isolated from the aorta to assess vasculogenesis. RESULTS: Prothrombin time was significantly shorter in ttw mice than in WT at 8 and 16 weeks. Fibrinogen had a greater increase in ttw mice than in WT at 16 weeks. The vascular area and vascular wall area were significantly smaller in ttw mice than in WT at all timepoints. The ratio of vascular wall area to vascular area was significantly smaller in ttw mice than in WT at 24 weeks. The endothelial cells from ttw mice formed significantly higher numbers of total branching points than WT cells. CONCLUSION: Ossification model mice had impaired blood coagulation and vascular morphology and high capacity for vasculogenesis. With regard to the pathogenesis of VTE, ttw mice harbor an environment that promotes the development of VTE.Level of Evidence: N/A.

Effect of teriparatide on ligamentum flavum mesenchymal stem cells isolated from patients with ossification of the posterior longitudinal ligament.

Ossification of the posterior longitudinal ligament (OPLL) within the spinal canal sometimes leads to severe myelopathy. Teriparatide (TPD) is a recombinant human parathyroid hormone (PTH) (1-34), which promotes osteogenesis of mesenchymal stem cells (MSCs) via PTH 1 receptor (PTH1R). Although ligamentum flavum (LF)-MSCs from patients with OPLL have a high osteogenic potency, the effect of TPD on them remains unknown. In this study, we determined PTH1R expression in LF-MSCs from patients with OPLL and investigated whether TPD promotes osteogenic differentiation in them. First, LF-MSCs were isolated from patients with OPLL and cervical spondylotic myelopathy (CSM) (controls). Cultured LF-MSCs were treated with different concentrations of TPD on days 0, 7, and 14. On day 21, osteogenic gene expression was quantified. Mineralization was measured based on optical density after Alizarin Red S staining. LF-MSCs from both groups expressed PTH1R at the same level. TPD did not enhance osteogenic gene expression and mineralization in LF-MSCs from both groups. TPD did not promote the osteogenic differentiation of LF-MSCs from patients with OPLL. Thus, it may be safe for patients with OPLL. However, further confirmation of our results with in vivo studies is necessary.

Ten-Year Long-term Results of Modified Cervical Double-door Laminoplasty With C3 Laminectomy Preserving the Semispinalis Cervicis Inserted Into the Axis Compared With Those of Conventional Cervical Laminoplasty.

STUDY DESIGN: A retrospective study. OBJECTIVE: To compare long-term clinical and radiologic outcomes between conventional double-door laminoplasty (LP) (group A) and cervical LP with C3 laminectomy (group B). SUMMARY OF BACKGROUND DATA: Cervical LP with C3 laminectomy preserving the semispinalis cervicis inserted into the axis decreased the patients' postoperative axial pain and muscle atrophy, prevented interlaminar bony fusion, decreased limitations of daily living activity, including reduced postoperative neck mobility, and maintained the cervical range of motion (ROM) more effectively than conventional cervical LP reattaching the semispinalis cervicis in the short-term. MATERIALS AND METHODS: Group A included 14 patients with an average age of 56.6 years at the time of surgery (follow-up rate 58.1%), and group B included 21 patients with an average age of 56.3 years at the time of surgery (follow-up rate 29.1%). We evaluated the clinical results, which included the Japanese Orthopaedic Association (JOA) score, JOA Cervical Myelopathy Evaluation Questionnaire (JOACMEQ), and radiologic results, including C2-C7 ROM, number of interlaminar bony fusions and presence of new spondylolisthesis at C3. RESULTS: There were no significant differences in preoperative and postoperative JOA scores, recovery rate of JOA score, and JOACMEQ. Significantly fewer patients in group B experienced interlaminar bony fusion at C2-C3 compared with those in group A. There was no significant difference in the presence of new spondylolisthesis at C3. In patients with cervical spondylotic myelopathy, the rate of decrease of C2-C7 ROM was significantly less in group B than in group A. In patients with ossification of the posterior longitudinal ligament, there was no significant difference in the rate of decrease of C2-C7 ROM between the groups. CONCLUSIONS: C3 laminectomy prevented interlaminar bony fusion at C2-C3. C3 laminectomy maintained cervical ROM in patients with cervical spondylotic myelopathy. There were no adverse events due to C3 laminectomy at 10 years postsurgery.

Eosinophilic Granulomatosis with Polyangiitis that was Difficult to Distinguish from Peroneal Nerve Palsy and Lumbar Disc Herniation: A Case Report.

Introduction: Eosinophilic granulomatosis with polyangiitis (EGPA) patients with mononeuropathy multiplex often visit orthopedic clinics; however, orthopedic surgeons have limited experience in diagnosing EGPA because of its rarity. We report a case of EGPA that required 1 month to confirm the diagnosis. Case Report: A 48-year-old woman presented with acute onset numbness in the right lower extremity. She had muscle weakness of the right lower extremity; lumbar spine magnetic resonance imaging showed lumbar disc herniation. Despite conservative treatment, her symptoms worsened. Blood tests showed increased eosinophils and serum IgE. She was diagnosed with EGPA, which should be considered in case of atypical paralytic symptoms. Conclusion: EGPA is so difficult to diagnose. In our case, the symptoms worsened on the 30th day after the initial visit. She was diagnosed with EGPA by a blood test at the time of admission. If patients with bronchial asthma or a history of allergies develop lumbar radiculopathy or peroneal nerve palsy-like symptoms, EGPA should be considered, and steroid treatment should be initiated early.

Can prophylactic C4/5 foraminotomy prevent C5 palsy after cervical laminoplasty with and without posterior instrumented fusion with maximal expansion?

OBJECTIVE: To prospectively examine whether laminoplasty with maximal expansion induces C5 palsy, even with prophylactic bilateral C4/5 foraminotomy. METHODS: Thirty-five consecutive patients with cervical myelopathy underwent laminoplasty (n = 19: LP group) or posterior decompression and fusion (n = 16: PDF group) with maximal expansion. Prophylactic bilateral C4/5 foraminotomy was performed alternately in consecutive five patients undergoing each type of surgery. In each type of surgery, the first and third consecutive five patients did not undergo foraminotomy (NF subgroup: 20 patients), while the second and fourth consecutive five patients underwent foraminotomy (F subgroup: 15 patients). The widths between the gutters was equivalent to the diameter of the spinal canal, and an inclination angle of the lamina of approximately 90° was created during laminoplasty. The incidence and severity of postoperative C5 palsy were investigated. Patients with a manual muscle testing score for the deltoid muscle and/or biceps brachii muscle of ≤ 2 were diagnosed with severe palsy. RESULTS: The respective incidences of C5 palsy in the F and NF subgroups were 33% and 20% in the LP group and 50% and 20% in the PDF group. Severe palsy occurred in 67% and 0% of patients who had developed palsy in F and NF subgroups, respectively, in the LP group, and in 100% of patients in the PDF group. Furthermore, 40% of the patients with severe palsy took more than 6 months to recover. CONCLUSIONS: Laminoplasty with maximal expansion induced C5 palsy in both the LP and PDF groups, even with the addition of prophylactic bilateral C4/5 foraminotomy.

Accuracy of pedicle screw placement by fluoroscopy, a three-dimensional printed model, local electrical conductivity measurement device, and intraoperative computed tomography navigation in scoliosis patients.

INTRODUCTION: There are several assisted methods for the accurate placement of pedicle screw (PS), including fluoroscopy, a three-dimensional (3D) printed model, a local electrical conductivity measurement device (LECMD), and intraoperative computed tomography (CT) navigation. OBJECTIVES: This study aimed to investigate the accuracy of PS placement and clinical results using different assisted methods. METHODS: This study included 553 pedicle screws in 31 patients. We divided patients into the fluoroscopy (F) group (n = 79), 3D printed model and fluoroscopy (3D + F) group (n = 150), LECMD, 3D printed model, and fluoroscopy (LECMD + 3D + F) group (n = 171), and the intraoperative CT navigation (N) group (n = 153). We evaluated the operative time, intraoperative bleeding, number of fusion vertebrae, correction rate of the main curve, apical vertebral translation, grade of PS perforation (Grade 0: no perforation; Grade 1: < 2 mm; Grade 2: 2‒4 mm; Grade 3: > 4 mm), and accuracy of PS placement. RESULTS: The N group had a significantly longer operative time. There were no significant differences in the clinical results excluding the operative time. The accuracy of PS placement was 93.7%, 91.3%, 93.6%, and 93.5% in the F, 3D + F, LECMD + 3D + F, and N groups, respectively. The Grade 2 perforation rate was 2.5%, 0%, 0.6%, and 0.7% in the F, 3D + F, LECMD + 3D + F, and N groups, respectively. CONCLUSIONS: There were no significant differences in the accuracy of PS placement and clinical results excluding the operative time. The 3D printed model, LECMD, or intraoperative CT navigation would be useful to prevent Grade 2 perforation.

Sex-Related Differences in Anxiety and Functional Recovery after Spinal Cord Injury in Mice.

It has been reported that female rats have a sex-related advantage in functional recovery and neuroprotection after spinal cord injury (SCI). However, the association between anxiety and neurological function after SCI in female and male rats remains unclear. The aim of this study was to examine sex-related differences in anxiety and neurological dysfunction after SCI in adult C57/BL6 male and female mice. After laminectomy at the 10th thoracic level, a contusive SCI was induced. The sham group received only a T10 laminectomy. Behavior testing (anxiety, motor/sensory function) was performed for 6 weeks after SCI. The spinal cord and preserved myelinated areas at the epicenter were histologically evaluated. Correlations between anxiety and motor/sensory function or histological parameters were analyzed using the Spearman correlation coefficient. Female and male mice showed significantly higher anxiety-like behaviors after SCI than before SCI. Anxiousness was significantly higher in female mice than in male mice after SCI. There was no significant difference in motor/sensory functions and histological features between the two groups. Anxiety-like behaviors were significantly correlated with sensory function at 2 weeks after SCI in female mice and with motor function at 2, 4, and 6 weeks after SCI in male mice. Anxiety-like behaviors were not significantly correlated with the spinal cord area at the epicenter in female and male mice. Our results revealed that female mice became more anxious than male mice after SCI. Anxiety-like behavior after SCI may be associated with functional recovery, and improving anxiety may affect functional recovery after injury.

Improvement in the results of the simple-foot-tapping test and cross-sectional area of the dural sac in patients with C5 palsy after posterior cervical spine surgery.

INTRODUCTION: The smaller cross-sectional areas of the dural sacs in patients without C5 palsy after posterior cervical spine surgery may lead to less neurological improvement. OBJECTIVES: The aim of this retrospective study was to clarify the differences in the cross-sectional area of the dural sac in the cervical spine and neurological improvement in patients with and without C5 palsy after posterior cervical spinal surgery. METHODS: We retrospectively evaluated the postoperative cross-sectional areas of the dural sacs and neurological outcomes in patients with and without C5 palsy after posterior cervical spine surgery. We compared the postoperative cross-sectional areas of the dural sac at C4/5 and C5/6 on magnetic resonance images between the C5 palsy group (n = 19) and the no-C5 palsy group (n = 84) after posterior cervical spinal surgery 1 year postoperatively. Performance tests, namely, the 10-s grip-and-release test and the 10-s single-foot-tapping (FT) test, were compared between the two groups. RESULTS: Postoperative cross-sectional areas of the dural sac at C4/5 and C5/6 (233.3 mm2 and 226.6 mm2, respectively) in the C5 palsy group were significantly larger (P = 0.0036 and P = 0.0039, respectively) than those (195.0 mm2 and 193.8 mm2, respectively) in the no-C5 palsy group. Postoperative gain in the grip-and-release test was similar between the two groups. Postoperative gain in the FT test (4.9 times) in the C5 palsy group was significantly larger (P = 0.0060) than that (1.8 times) in the no-C5 palsy group. CONCLUSIONS: In the C5 palsy group 1 year after posterior cervical spine surgery, the cross-sectional areas of the dural sac were larger, and the 10-s single FT test improved noticeably.