Postoperative Japanese Orthopaedic Association Research Articles

Long-term Results Regarding the Instability of Decompressive Surgery without Fusion for Degenerative Spondylolisthesis

The long-term results of decompressive surgery for degenerative spondylolisthesis (DS) were evaluated with reference to instability. Patients (n=48) undergoing decompressive surgery without fusion were studied. The diagnosis of spondylolisthesis was made based on the presence of sagittal vertebral slippage greater than 3mm. Instability was defined as translation more than 2mm on lateral functional radiography. Surgical interventions were divided into two groups: bilateral laminotomy (n=25)and laminectomy (n=23). Clinical results were evaluated according to the McCulloch's classification and Japanese Orthopedic Association(JOA)score. Of 48 patients, 25 showed preoperative instability. Eleven patients showed both pre-and postoperative instability. The mean pre-and postoperative slippages were 7.5 and 7.6mm, respectively. Of 23 patients without preoperative instability, nine developed postoperative instability. In this group, slippage changed from 6.2 to 6.1mm. Instability was not related to slippage progression. Surgical results of patients undergoing laminotomy were superior to those undergoing laminectomy. The mean pre-and postoperative JOA scores and recovery rate were 14.5, 20.9, and 63.1 in instability group patients with laminotomy and 15.6, 23.2, and 59.0 in the non-instability group, respectively. Surgical results were similar and not related to preoperative instability. Low back pain (LBP) showed no correlation to the degree of slippage, instability, and surgery type. LBP improved in each group. Instability, defined by vertebral translation on lateral functional radiography, did not affect the surgical results of patients with DS treated with laminotomy.

Comparison of anterior approach versus posterior approach for the treatment of multilevel cervical spondylotic myelopathy

The purpose of this study is to evaluate the clinical outcomes, complications, and surgical trauma between anterior and posterior approaches for the treatment of multilevel cervical spondylotic myelopathy (CSM). Systematic review and meta-analysis. Randomized controlled trials or non-randomized controlled trials published up to November 2014 that compared the clinical effectiveness of anterior and posterior surgical approaches for the treatment of multilevel CSM were acquired by a comprehensive search in four electronic databases (PubMed, EMBASE, Cochrane Controlled Trial Register and MEDLINE). Exclusion criteria were non-controlled studies, combined anterior and posterior surgery and cervical myelopathy caused by ossification of the posterior longitudinal ligament. The main end points included: recovery rate; Japanese Orthopedic Association (JOA) score; complication rate; reoperation rate; blood loss; operation time and length of stay. A total of ten studies were included in the meta-analysis; none of which were randomized controlled trials. All of the selected studies were of high quality as indicated by the Newcastle-Ottawa scale. In six studies involving 467 patients, there was no significant difference in the preoperative JOA score between the anterior surgery group and the posterior group [P > 0.05, WMD -0.00 (-0.50, 0.50)]. In four studies involving 268 patients, the postoperative JOA score was significantly higher in the anterior surgery group compared with the posterior surgery group [P < 0.05, WMD 0.79 (0.16, 1.42)]. In five studies involving 420 patients, there was no statistically significant difference in recovery rate between the anterior and posterior surgery groups [P > 0.05, WMD 2.73 (-8.69, 14.15)]. In nine studies involving 804 patients, the postoperative complication rate was significantly higher in the anterior surgery group compared with the posterior surgery group [P = 0.009, OR 1.65 (1.13, 2.39)]. In five studies involving 294 patients, the reoperation rate was significantly higher in the anterior surgery group compared with the posterior surgery group [P = 0.0001, OR 8.67 (2.85, 26.34)]. In the four studies involving 252 patients, the intraoperative blood loss and operation time was significantly higher in the anterior surgery group compared with the posterior surgery group [P < 0.05, WMD -40.25 (-76.96, -3.53) and P < 0.00001, WMD 61.3 (52.33, 70.28)]. In the three studies involving 192 patients, the length of stay was significantly lower in the anterior surgery group compared with the posterior surgery group [P < 0.00001, WMD -1.07 (-2.23, -1.17)]. In summary, our meta-analysis suggested that a definitive conclusion could not be reached regarding which surgical approach is more effective for the treatment of multilevel CSM. Although anterior approach was associated with better postoperative neural function than posterior approach in the treatment of multilevel CSM, there was no apparent difference in the neural function recovery rate between the two approaches. Higher rates of surgery-related complication and reoperation should be taken into consideration when anterior approach is used for patients with multilevel CSM.

Surgical outcome and prognostic factors of anterior decompression and fusion for cervical compressive myelopathy due to ossification of the posterior longitudinal ligament

Background contextAnterior decompression and fusion (ADF) for ossification of the posterior longitudinal ligament (OPLL) is technically demanding and associated with complications. Although various factors affecting clinical outcome have been investigated in posterior decompression, prognostic factors of ADF remain unclear. PurposeThe purpose of the study was to identify surgical outcome and prognostic factors of ADF for cervical myelopathy due to OPLL. Study designThis was a retrospective case study. Patient sampleBetween 2005 and 2012, 913 patients underwent decompression surgery for cervical OPLL at our institution. Among them, 131 who underwent ADF and 221 who underwent laminoplasty were enrolled. Inclusion criteria were (1) diagnosis of OPLL; (2) cervical compressive myelopathy; and (3) no trauma, infection, tumor, or previous surgery. We excluded 60 patients with ADF and 157 patients with laminoplasty owing to inadequate follow-up or absence of preoperative myelopathy. Finally, 71 patients with ADF and 64 patients with laminoplasty were enrolled in this study (mean follow-up, 48 vs 41 months). Outcome measuresNeurologic assessment was conducted using the Japanese Orthopedic Association (JOA) scoring system for cervical myelopathy. Rate of neurologic improvement was calculated by comparing preoperative and postoperative JOA scores. MethodsWe investigated the effects of such variables as age, gender, body mass index (BMI), presence of diabetes mellitus (DM), smoking history, type of OPLL, shape of the ossified lesion, occupying ratio of OPLL, presence of intramedullary increased signal intensity (ISI) on magnetic resonance imaging (MRI), and sagittal alignment of the cervical spine on surgical outcome. Severity of ISI was classified into three groups based on T2-weighted sagittal MRI as follows: Grade 0, none; Grade 1, ISI limited to one disc level; or Grade 2, ISI beyond one disc level. This work was supported by the 2013 Korea Health Technology R&D Project of the Ministry of Health and Welfare of the Republic of Korea (A120254). ResultsIn patients with an occupying ratio ≥60% or with presence of ISI on MRI, ADF yielded better surgical outcome than laminoplasty. A higher ISI grade (B=−28.5, p=.000) and a higher occupying ratio (B=0.88, p=.04) were significantly associated with a lower recovery rate (R=0.56, p=.006). Older age also was associated with a lower recovery rate. Gender, BMI, presence of DM, smoking history, type of OPLL, shape of the ossified lesion, and cervical alignment were not associated with recovery rate. ConclusionAnterior decompression and fusion has favorable outcome in patients with an occupying ratio ≥60% or with presence of ISI on MRI. Presence of higher ISI grade, higher occupying ratio, and older age were associated with a poor long-term surgical prognosis. Therefore, evaluating ISI and occupying ratio on preoperative MRI is important for selecting the appropriate surgical approach and for predicting clinical outcome after surgery for cervical compressive myelopathy due to OPLL.

Patient outcomes for a minimally invasive approach to treat lumbar spinal canal stenosis: Is microendoscopic or microscopic decompressive laminotomy the less invasive surgery?

ObjectiveWe performed a study to compare the severity of surgical stress between microscopic and microendoscopic decompressive laminotomy performed via a unilateral approach in patients with lumbar spinal canal stenosis (LSCS). Materials and methodsA total of 41 patients received decompressive laminotomy for lumbar spinal stenosis. Twenty patients received microscopic decompressive laminotomy (MDL), and 21 patients received microendoscopic decompressive laminotomy (MEDL). The pre- and postoperative Japanese Orthopaedic Association (JOA), and Visual Analogue Scale (VAS) lower leg pain scores were evaluated. The other variables studied were the length of the operation, blood loss, length of hospital stay, the reaction of the CRP and WBC levels, the dosage of non-steroidal anti-inflammatory drugs (NSAIDs) used and surgical complications. ResultsThe clinical analyses of the surgical outcomes were evaluated after a minimum two-year follow-up. The pre-and postoperative JOA scores and VAS in the MDL and MEDL groups were statistically similar. There were statistically significant differences found between the lengths of the operation time, blood loss, length of hospital stay, the reaction of CRP, and the pain indicated by the dosage of NSAIDs. The length of the operation time was longer in the MEDL group, and the other variables were greater in the MDL group. ConclusionsThe MEDL procedure is less invasive and safer than the MDL procedure. Hence, MEDL is an effective technique for treating symptomatic LSCS patients.

Surgical Outcome for Hemodialysis-Related Upper Cervical Lesions.

Study DesignA retrospective study.PurposeTo investigate the surgical outcome for hemodialysis-related upper cervical lesions.Overview of LiteratureSurgical outcome of lower cervical lesions in patients undergoing hemodialysis has been reported. However, surgical outcome for upper cervical lesions in hemodialysis patients is unclear.MethodsUpper cervical lesions in nine patients undergoing hemodialysis were surgically treated. Mean age at surgery was 61.6 years (range, 52-68 years), and the mean follow-up period was 45.4 months (range, 2-98 months). Patients had undergone hemodialysis for an average of 25.3 years (range, 16-40 years) at surgery. Seven patients with destructive spondyloarthropathy (DSA) of the upper cervical spine were treated with atlantoaxial or occipitocervical fixation. Two patients with retro-odontoid pseudotumors were treated with C1 posterior arch resection alone. Japanese Orthopedic Association (JOA) scores for cervical myelopathy, postoperative complications, postoperative radiography, and preoperative and postoperative occipital pain were evaluated.ResultsMean preoperative and postoperative JOA score was 3.7 and 8.1, respectively. The seven patients with DSA had severe preoperative occipital pain that disappeared postoperatively. Postoperative radiography showed solid bone union in DSA cases and no instability in pseudotumor cases.ConclusionsSatisfactory surgical outcome was observed for hemodialysis-related upper cervical lesions.

Age-related surgical outcomes of laminoplasty for cervical spondylotic myelopathy.

Study Design Retrospective clinical study. Objective To investigate the age-related surgical outcomes of laminoplasty. Methods One hundred patients who underwent an en bloc laminoplasty for cervical spondylotic myelopathy from 2004 to 2008 and were followed for at least 1 year were included in this study. The clinical outcomes were assessed with the Japanese Orthopaedic Association (JOA) score. Acquired points (postoperative JOA score minus preoperative JOA score) were also calculated. To investigate the age-related effect for laminoplasty, two analyses were conducted: (1) the correlation between age and clinical outcome; and (2) the clinical outcomes by decade. Patients were divided into four groups according to their age at the time of operation as follows: group 50s, 50 to 59 years old; group 60s, 60 to 69 years; group 70s, 70 to 79 years; and group 80s, 80 to 89 years. The pre- and postoperative JOA scores, acquired points, preoperative comorbidities, and postoperative complications were then compared among the groups. Results Significant correlations were detected between age and JOA scores at the preoperative (p = 0.03), postoperative maximum (p < 0.0001), and final assessments (p < 0.0001). An age-related decline of JOA scores was observed over all periods. The analysis by decades showed the same results. On the other hand, the significant differences were not found for acquired points over all periods by either method. The preoperative comorbidities of hypertension and diabetes mellitus increased with age. Delirium was more common postoperatively in elderly patients. Conclusions Although an age-related decline of JOA scores was found over all periods, there were no severe sequelae and no differences in the acquired points that were age-related.

Long-term results of decompressive surgery without fusion for degenerative spondylolisthesis

The long-term results of decompressive surgery for degenerative spondylolisthesis with symptomatic lumbar spinal stenosis were evaluated retrospectively with regard to the postoperative progression of slippage and clinical symptoms. The study included 53 patients who underwent surgery, and for whom follow-up of at least 5 years was conducted. Spondylolisthesis was diagnosed based on the presence of sagittal vertebral translation greater than 3mm on lateral radiographs. The patients were divided into two groups:Group I:37 patients undergoing bilateral laminotomy, and Group II:16 patients undergoing laminectomy. The clinical results were evaluated according to McCulloch's classification and the Japanese Orthopaedic Association(JOA)score. The mean pre-and postoperative JOA scores were 14.6 and 22.9 in Group I and 14.7 and 21.0 in Group II, respectively. The JOA scores improved soon after surgery, after which the scores declined gradually in both groups. The recovery rate was 63.0% in Group I and 43.7% in Group II. The average amount of pre- and postoperative slippage was 7.3mm and 6.9mm in Group I and 6.2mm and 6.9mm in Group II, respectively. In Group I, the slippage progressed within the first year, after which the degree of slippage slowly decreased to lower values than those observed preoperatively, whereas slippage progressed for 5 years before declining in Group II. No correlations were observed between progression of slippage and clinical outcomes in either group. Laminotomy produces satisfactory long-term results both clinically and radiographically in patients with degenerative spondylolisthesis.

Cervical spondylotic myelopathy caused by single-level vertebral spontaneous fusion.

PurposeTo evaluate the clinical features, imaging characteristics, surgical options, and clinical outcomes of patients with Cervical spondylotic myelopathy (CSM) caused by single-level vertebral spontaneous fusion (SLVSF).MethodsSixteen consecutive patients with SLVSF who underwent anterior surgery were included in this study and 38 patients with CSM caused by spinal degeneration were enrolled as a control group. Demographic features, clinical presentations, imaging characteristics, surgery strategy, Nurick grade, Japanese Orthopedic Association (JOA) score, neck disability index (NDI), and complications were evaluated.ResultsThere were significant differences between the two groups in the mean age and the average duration of neck pain. There was no significant difference between the two groups in length of cervical spine. In the SLVSF group, 13 patients had upper segment translational instability and none had rotational instability. Pre- and postoperative Nurick grades were 2.94±0.77 and 2.19±0.54 in the SLVSF group, and 2.97±0.72 and 2.16±0.64 in the control group. Pre- and postoperative JOA scores were 9.25±2.02 and 11.69±1.62 in the SLVSF group, and 9.87±2.58 and 12.53±2.69 in the control group. Pre- and postoperative NDI values were 28.5±7.75 and 15.56±5.51 in the SLVSF group, and 16±6.13 and 11.29±4.58 in the control group.ConclusionsPatients with SLVSF have necks of normal lengths, which can be used to distinguish this disorder from Klippel-Feil syndrome. There are three main features of SLVSF: (1) hypoplasia at both of the spontaneously fused vertebral bodies; (2) a major pathological feature of translational instability of the upper vertebra to the fused level; and (3) severe neck pain. Anterior surgery has a good therapeutic effect for patients with cervical SLVSF.

Double-door laminoplasty for treatment of cervical whiplash injury

Objective To analyze efficacy of double door laminoplasty for treatment of whiplash injury of the cervical spine.Methods Forty-one cases of cervical whiplash injury treated surgically from January 2001 to October 2011 and available to follow up were analyzed retrospectively.There were 32 males and 9 females with mean age of (51.0 ± 12.0) years (range,28 to 74 years).Causes of injury included traffic accidents in 30 cases,fall on the ground in 8,and high fall in 3.All cases were combined with developmental cervical stenosis and six with ossification of the posterior longitudinal ligament.Posterior double-door laminoplasty was operated in 36 cases and one-stage surgery via anterior-posterior approach in 5 cases.Cases were grouped according to their ages,preoperative cervical Japanese Orthopedic Association (JOA) score,and operation time.Results were compared among groups.Results Operation lasted for 70-180 minutes (mean,121.9 minutes) and showed blood loss of 30-500 ml (mean,177.8 ml).All cases were followed up for 12 to 110 months (mean,59.4 months).Overall JOA score averaging 14.7 points improved significantly after operation with mean improvement rate of 77.8％ (P ＜0.01).Whereas between non-elderly and elderly groups,postoperative JOA improvement rate [(79.6 ± 18.8)％ vs (73.5 ±22.8)％] and excellent rate (90％ vs 83％) were similar.For cases grouped according to their preoperative JOA score,the results were satisfactory for all groups,but the differences were insignificant.Besides,JOA score at the last follow-up differed significantly among groups (P ＜ 0.0l).Improvement rate of JOA score was better in early surgery group than in late surgery group [(84.6±13.3)％ vs (75.4±24.0)％,P＜0.05].Conclusions Double door laminoplasty is reliable in treatment of cervical whiplash injury on condition that surgical indications are grasped strictly.Elderly or gravely injured patients can also have considerable recovery of neurological function,but patients with severe injury or late surgery are associated with poor prognosis. Key words: Spinal cord injuries; Cervical vertebrae; Whiplash injury

Surgical treatment for cervical spondylotic myelopathy with different characteristics in imaging examinations

Objective To investigate the clinical features, operation procedures and clinical outcomes of cervical spondy-lotic myelopathy with different imageological characteristics. Methods Two hundred and twenty one cervical myelopathy with different imageological characteristics patients between November 2011 and October 2013 were involved in this retrospective study. Patients were distributed into three groups, namely mild group （A）, moderate group （B） and severe group（C）, based on severi-ty of complexity by imageological variables （severity of cervical spine degeneration, the number of spinal cord compression, severi-ty of spinal cord compression and difficulty in operation）. Preoperative and postoperative Japanese Orthopaedic Association （JOA） score and mean recovery rate were collected to evaluate the postoperative clinical effects. Demographic data and imageological characteristics were recorded;Univariate analysis or analysis of variance was conducted to analyze the correlation between post-operative JOA recovery rate with gender, age, course of disease, severity of spinal cord compression, the number of segment with spinal cord compression, severity of disc degeneration, MRI T2 increased signal intensity, cervical instability, cervical kyphosis, developmental cervical spinal stenosis and ossification of posterior longitudinal ligament. Results There was no significant differ-ence in gender between three groups. There was significant difference in age, preoperative JOA score and improvement rate be-tween group A and group B （C）. All patients received decompression and reconstruction by anterior or posterior approach. The ra-tio of anterior approach in group A, B and C was 91.1%（72/79）, 79.8%（71/89）, 35.8%（18/53）. The last follow-up JOA recovery rate of group A, B and C was 75.4%±6.4%、67.7%±8.7%、62.8%±10.4%. The last follow-up JOA recovery rate was correlated with duration of disease, the number of spinal cord compression and severity of spinal cord compression. Age, duration of course, preop-erative JOA score, degree of cord compression, the number of segment with cord compression, degree of disc degeneration, MRI T 2 increased signal intensity, cervical instability, cervical kyphosis, developmental cervical spinal stenosis and OPLL. Conclusion Patients suffering from cervical myelopathy with different imageological have good prognosis by appropriate operation procedure. Key words: Cervical spondylosis Magnetic resonance imaging Surgical procedures; operative

Changes of sagittal balance of cervical spine after open-door expansive laminoplasty

To explore the changes of sagittal balance of cervical spine after open-door expansive laminoplasty. The clinical and radiological data were analyzed retrospectively for 90 patients undergoing open-door expansive laminoplasty due to cervical spondylotic myelopathy. The Japanese Orthopedic Association (JOA) score and 3 cervical sagittal parameters including C2-C7 SVA, C0-2 Cobb angle and T1-Slope on lateral view radiographs were recorded before operation and at the final follow-up. The average follow-up period was 16.7 (3-40) months. The post-operative JOA score rose to 14.6 ± 0.2 from pre-operative 12.2 ± 0.3 with 43.5% ± 4.2% recovery rate. The post-operative values of C2-C7 SVA, C0-2 Cobb angle and T1-Slope were significantly different from pre-operative ones (P = 0.022, P < 0.001, P = 0.002) . C2-C7 SVA increased to (23.0 ± 1.2) mm from pre-operative (20.7 ± 1.1) mm. C0-2 Cobb angle increased (23.1 ± 0.8) ° from pre-operative (19.9 ± 0.8)°; T1-Slope increased to (26.2 ± 0.7)° from pre-operative (25.1 ± 0.7)°. The changes of C0-2 Cobb angle and T1-Slope were correlated with that of C2-C7 SVA respectively (Pearson = 0.469, P < 0.001) (Pearson = 0.303, P = 0.004) . Patients with higher preoperative T1-Slope had less JOA improvement (31.5% vs 53.7%, P = 0.019) than those with lower preoperative T1-Slope after laminoplasty. The sagittal balance of cervical spine significantly changes after open-door expansive laminoplasty with forward tilting of cervical vertebra. And compensation occurs by excessive high-strength contraction of posterior muscles to maintain lordosis in upper cervical spine. A higher pre-OP T1-Slope affects the outcomes of open-door expansive laminoplasty.

Rapid progressive clinical deterioration of cervical spondylotic myelopathy.

Retrospective clinical study. To elucidate the pathophysiology of rapid progressive clinical deterioration following the onset of cervical myelopathy. Spinal Injuries Center, Fukuoka, Japan. A total of 43 cervical spondylotic myelopathy (CSM) patients were treated surgically by a senior surgeon. All patients showed intramedullary intensity changes on magnetic resonance (MR) imaging. Overall, eight patients suffered rapid progressive clinical deterioration; four of them had obvious anamnesis of minor trauma. We assessed the responsible injured segment by MR T2-weighted images. Clinical instabilities at the focal segment were evaluated using functional sagittal plain radiographs. Neurological evaluations were performed preoperatively and at 12 months postoperatively using American Spinal Injury Association (ASIA) motor scores and Japanese Orthopaedic Association (JOA) scores for cervical myelopathy. Intraoperatively, we evaluated the presence of adhesive scar tissue on the dura mater at the focal segment. The responsible injured segment was C3-4 in 75% of the rapid progressive (rp)-CSM and in 28.57% of the conventional CSM subjects. One with rp-CSM showed sagittal translational segmental instability. Preoperative ASIA motor scores and JOA scores in the rp-CSM were significantly lower than those in the conventional CSM subjects. Postoperative ASIA motor scores between the subjects showed no significant differences; however, postoperative JOA scores in the rp-CSM subjects were significantly lower. Moreover, an epidural membrane was observed in 62.5% of rp-CSM and 11.4% of conventional CSM subjects. We hypothesized that the pathophysiology of rp-CSM might be additional cervical cord disorder following the onset of cervical myelopathy. Early decompression surgery is recommended in such patients.

Surgical strategies for ossified ligamentum flavum associated with dural ossification in thoracic spinal stenosis

We describe two surgical strategies for treating thoracic spinal stenosis (TSS) with ossification of the ligamentum flavum (OLF) and dural ossification (DO), and discuss their postoperative efficacy. From January 2004 to June 2008, 147 patients underwent TSS surgery. Thirty three of those with intraoperative evidence of OLF and DO were included in the present study. Based on the different intraoperative treatment of the dura, these 33 patients were divided into two groups: Group A, 17 patients who had their dura slit and the ossification excised, and Group B, 16 patients treated by floating the ossified dura by thinning it with a drill. All patients underwent outpatient follow-up. Pre- and postoperative Japanese Orthopaedic Association (JOA) scores and recovery rates were evaluated. The mean follow-up period was 42months. The incidence of DO with OLF in TSS was 22%. At 1 year follow-up, the mean JOA score improved from 5.12±1.17 to 6.94±0.90 in Group A and from 5.25±1.34 to 7.13±1.41 in Group B. Additionally, the mean JOA score improved from 5.18±1.24 to 7.03±1.16 in TSS patients with DO and from 5.52±1.21 to 7.21±1.18 in TSS patients without DO. The increased cross-sectional area of the pre- and postoperative dural sac at the level of stenosis suggested that decompression was complete. Both decompression methods are feasible for curing TSS with OLF and DO. Moreover, slitting the dura for ossified dura and ligamentum flavum removal to relax the spinal cord is a safe and reliable method. Even though it increased the surgical difficulties and risks, DO did not affect postoperative neurological recovery.

Individualized Treatment of Complex Craniovertebral Junction Abnormalities by Intraoperative Computed Tomography and Navigation System

Background: Treatment of complex craniovertebral junction abnormalities (CCJA) with ventral cervicomedullary compression is challenging due to the aberrant anatomic structures. The exact site of the compression is usually away from the midline. The intraoperative CT and navigation system is helpful for the localization. Objective: To assess the feasibility and potential utility of this system in individualized treatment of CCJA. Methods: We applied this technology to endoscopic transnasal or microsurgical transoral odontoidectomy and/or clivusectomy in 25 cases, odontoidectomy through posterior midline approach in 1 case, and transoral C1 lateral mass resection in 1 case. The pre- and postoperative neurologic status was examined. Results: No neurovascular injury occurred during surgery. Neuronavigation was found to correlate well with the intraoperative findings. All the patients had the improvement of the presenting clinical symptoms. The mean postoperative Japanese Orthopedic Association score was 14.9, compared with the preoperative score of 10.6 (p < 0.01). One case had postoperative pulmonary infection and one case with clivusectomy had the rupture of the dura mater and leakage of cerebrospinal fluid. Conclusions: For some complicated situations of the craniovertebral junction abnormalities, the treatment strategies should be tailored and individualized and the intraoperative CT-based navigation is an effective method to be considered.

AB0294 Preoperative Factors Associated with Outcomes of Total Hip Arthroplasty in Rheumatoid Arthritis

BackgroundAlthough the outcomes of total hip arthroplasty (THA) for rheumatoid arthritis (RA) is reported to be comparable with osteoarthritis (OA) patients in terms of fixation of implants, symptoms are often...

Electrophysiological evidence of functional improvement in the corticospinal tract after laminoplasty in patients with cervical compressive myelopathy: clinical article.

Cervical laminoplasty is a surgical procedure for cervical compressive myelopathy (CCM), and satisfactory outcomes have been reported. However, few reports have examined the pathophysiology of improvements in spinal cord function. The aim of this study was to investigate the variation in central motor conduction time (CMCT) before and after cervical laminoplasty in patients with CCM. Motor evoked potentials (MEPs) following transcranial magnetic stimulation and compound muscle action potentials (CMAPs) and F-waves following electrical stimulation of the ulnar and tibial nerves at the wrist and ankle were measured from the abductor digiti minimi muscle (ADM) and abductor hallucis muscle (AH) in 42 patients with CCM before and 1 year after cervical laminoplasty. The peripheral conduction time (PCT) was calculated as follows: (latency of CMAPs + latency of F-waves - 1)/2. The CMCT was calculated by subtracting the PCT from the onset latency of the MEPs. The CMCT recovery ratio was defined and calculated as the ratio of CMCT values 1 year after surgery to those before surgery. The CMCT data were analyzed as longer or shorter CMCT between the patients' right and left ADMs and AHs. The Japanese Orthopaedic Association (JOA) score for cervical myelopathy was obtained as a clinical outcome before and 1 year after surgery. The recovery rate (RR) 1 year after surgery was calculated using the following formula: (postoperative JOA score 1 year after surgery - preoperative JOA score)/(17 - preoperative JOA score) × 100. Correlations among CMCT parameters, patient age, JOA score, and RR were determined. The longer and shorter CMCTs from the ADM (longer, p = 0.000; shorter, p = 0.008) and the longer CMCT from the AH (longer, p = 0.000) before surgery decreased significantly 1 year after surgery; the shorter CMCT from the AH did not significantly differ (shorter, p = 0.078). The mean JOA score before surgery was 10.1 ± 3.0 and improved significantly to 12.9 ± 2.7 at 1 year after surgery (p = 0.000). The mean CMCT recovery ratio and RR were 0.91 ± 0.18 and 0.43 ± 0.27, respectively. The longer/shorter CMCT parameters in the ADM and AH before or 1 year after surgery correlated significantly with the JOA score both before and 1 year after surgery. The CMCT recovery ratio from the longer CMCT in the ADM correlated significantly with the RR (r = - 3090, p = 0.011). There were no significant correlations between age and any CMCT parameters or CMCT recovery ratios. These results suggest that cervical laminoplasty improves corticospinal tract function 1 year after surgery, which may be one of the reasons for the JOA score improvements in patients with CCM. The degree of improvement in corticospinal tract function did not correlate with patient age in this case series. The results demonstrated quantitative evidence of the pathophysiology of functional recovery in the corticospinal tract following cervical laminoplasty in patients with CCM.

Cervical microendoscopic interlaminar decompression through a midline approach in patients with cervical myelopathy: a technical note.

Microendoscopic techniques through a unilateral paramedian approach or muscle-preserving techniques using a microscope have been reported as minimally invasive spinal decompression procedures for the cervical spine. In this study, we developed a novel technique, cervical microendoscopic interlaminar decompression (CMID) through a midline approach, for treating cervical compression myelopathy. A total of 29 consecutive patients with single- or two-level cervical compression myelopathy were reviewed. For the single-level cases (e.g., C5-C6), a midline skin incision, ∼ 2 cm in length, was made at the spinal level to be decompressed (C5-C6) under fluoroscopic guidance. The nuchal ligament was longitudinally cut, and tips of the spinous processes (C5 and C6) were exposed. A 16-mm tubular retractor was inserted between the tips of the C5 and C6 spinous processes. A dome-like laminectomy of C5, partial laminectomy of the upper part of C6, and flavectomy were performed. For the two-level cases (e.g., C4-C5 and C5-C6), the decompression procedure was completed by splitting the spinous process (C5). Pre- and postoperative neurologic status was evaluated using the Japanese Orthopedic Association (JOA) score. Neck and arm pain was also evaluated using a numerical rating scale (NRS). Overall, 10 patients underwent single-level decompression, and 19 patients underwent two-level decompression. The average age was 67 years (range: 40-83 years), and the mean follow-up period was 11 months (range: 4-14 months). The average pre- and postoperative JOA scores were 10.2 and 13.5, with a mean recovery rate of 49%. The mean preoperative and postoperative NRS scores were 3.5 and 1.5 for neck pain and 4.6 and 2.9 for arm pain, respectively. One patient showed transient mild weakness of the leg that recovered neurologically within a few weeks. No other postoperative complications were observed. This procedure revealed good short-term surgical results. This technique has advantages including (1) a symmetrical orientation of the surgical field, (2) an intermuscular incision that minimizes blood loss and muscle trauma, and (3) the ability to safely complete the decompression procedure without retracting the cervical spinal cord compared with the unilateral approach. Although long-term surgical results are required, this technique is not only safe but also minimally invasive as a treatment for cervical compression myelopathy.

Laminoplasty and laminectomy hybrid decompression for the treatment of cervical spondylotic myelopathy with hypertrophic ligamentum flavum: a retrospective study.

ObjectiveTo report the outcomes of a posterior hybrid decompression protocol for the treatment of cervical spondylotic myelopathy (CSM) associated with hypertrophic ligamentum flavum (HLF).BackgroundLaminoplasty is widely used in patients with CSM; however, for CSM patients with HLF, traditional laminoplasty does not include resection of a pathological ligamentum flavum.MethodsThis study retrospectively reviewed 116 CSM patients with HLF who underwent hybrid decompression with a minimum of 12 months of follow-up. The procedure consisted of reconstruction of the C4 and C6 laminae using CENTERPIECE plates with spinous process autografts, and resection of the C3, C5, and C7 laminae. Surgical outcomes were assessed using Japanese Orthopedic Association (JOA) score, recovery rate, cervical lordotic angle, cervical range of motion, spinal canal sagittal diameter, bone healing rates on both the hinge and open sides, dural sac expansion at the level of maximum compression, drift-back distance of the spinal cord, and postoperative neck pain assessed by visual analog scale.ResultsNo hardware failure or restenosis was noted. Postoperative JOA score improved significantly, with a mean recovery rate of 65.3±15.5%. Mean cervical lordotic angle had decreased 4.9 degrees by 1 year after surgery (P<0.05). Preservation of cervical range of motion was satisfactory postoperatively. Bone healing rates 6 months after surgery were 100% on the hinge side and 92.2% on the open side. Satisfactory decompression was demonstrated by a significantly increased sagittal canal diameter and cross-sectional area of the dural sac together with a significant drift-back distance of the spinal cord. The dural sac was also adequately expanded at the time of the final follow-up visit.ConclusionHybrid laminectomy and autograft laminoplasty decompression using Centerpiece plates may facilitate bone healing and produce a comparatively satisfactory prognosis for CSM patients with HLF.

Impact of Diabetes on the Outcomes of Cervical Laminoplasty

A prospective cohort study. This study aimed to compare the outcome of cervical laminoplasty between diabetic patients and nondiabetic patients with cervical spondylotic myelopathy. A few retrospective studies have investigated the outcomes of cervical myelopathy in diabetic patients; therefore, our large-scale cohort study was designed to assess these outcomes in cervical spondylotic myelopathy. In total, 505 consecutive patients with cervical spondylotic myelopathy (311 males, 194 females; mean age, 66.6 yr; range, 41-91 yr) who underwent double-door laminoplasty were prospectively enrolled. They were followed up for more than 12 months after surgery (mean follow-up period, 25.6 ± 12.6 mo). The patients were divided on the basis of diabetic criteria for glucose intolerance into 2 groups: the diabetic group (n = 105) and nondiabetic group (n = 400). We evaluated differences in pre- and postoperative Japanese Orthopaedic Association (JOA) scores, recovery rate, achieved JOA scores (postoperative JOA score - preoperative JOA score), and complications between both groups. The mean JOA scores in the diabetic and nondiabetic groups were 10.1 and 10.8 points before surgery and 13.1 and 13.9 points after surgery, respectively. The diabetic group showed significantly low pre- and postoperative JOA scores and low recovery rate of JOA scores compared with the nondiabetic group (47.3% vs. 53.6%, P < 0.05). However, mean achieved JOA scores in the diabetic and nondiabetic groups were 3.0 and 3.1 points respectively, with no significant difference between both groups (P = 0.343). The groups showed no significant difference in the postoperative complication rate. Pre- and postoperative JOA scores and recovery rates were lower in the diabetic group than the nondiabetic group. However, the achieved JOA scores were not significantly different between both groups. Diabetic and nondiabetic patients experienced similar benefits from laminoplasty. 3.

Extraforaminal compression of the L-5 nerve root at the lumbosacral junction: clinical analysis, decompression technique, and outcome

Extraforaminal compression of the L-5 nerve encompasses multiple pathological entities and may result from disc herniations as well as bony (osteophytes or sacral ala) or ligamentous (sacroiliac ligament and lumbosacral band) compression. Several other factors, such as disc space collapse or coronal wedging, can also contribute to narrowing of the extraforaminal space. The extraforaminal space at L5-S1 has unique anatomical features compared with the upper lumbar levels, which makes surgical access to this region difficult. Minimally invasive techniques offer easier access to the region. The purpose of this study was to analyze the contributing factors for extraforaminal compression of the L-5 nerve and assess clinical outcome following surgical decompression. Fifty-two consecutive patients who underwent a minimally invasive far-lateral approach for extraforaminal compression of the L-5 nerve were retrospectively analyzed for clinical data, outcomes, and imaging features (type of disc prolapse, coronal wedging, degree of disc and facet degeneration, facet tropism, foraminal stenosis, osteophytes, and adjacent-level disease). The authors describe the surgical technique used in this study. The mean age of the patient sample was 57 years. Sixteen patients each had an extraforaminal ruptured disc or contained protrusion, and the remaining 20 patients had disc protrusions extending into the foraminal region or the lateral recess. Associated foraminal stenosis was found in 38.5%, and adjacent-level stenosis was noted in 22 cases (42.3%) and spondylolisthesis in 4 (7.7%). Osteophytes were noted in 18 cases. A coronal wedging angle ≥ 3° was found in 46.2%, and the laterality of wedging corresponded to the symptomatic side in 91% of cases. Fifteen patients (28.8%) complained of postoperative dysesthesias, which completely resolved in all cases within 6 months. The incidence of dysesthesias was more common in the ruptured disc group. There were no differences in clinical outcome among the different types of disc prolapses. The mean preoperative and postoperative visual analog scale scores were 7.6 and 3.6, respectively. The mean preoperative and postoperative Japanese Orthopaedic Association (JOA) scores were 6.4 and 13.8, respectively. The mean JOA recovery rate was 86.1%. According to the Macnab functional grading system, 96% of the patients had excellent or good grades at follow-up. A minimally invasive far-lateral approach to L5-S1 requires a good understanding of the regional anatomy and can provide good to excellent clinical results in properly selected cases. This approach is effective in decompressing the far-lateral and foraminal zones. Adequate preoperative diagnosis and tailoring the surgical procedure to address the relevant compressive element in each case is essential to achieving good clinical results.