Comparison of Perioperative Complications in Anterior Decompression With Fusion and Posterior Decompression With Fusion for Cervical Ossification of the Posterior Longitudinal Ligament: Propensity Score Matching Analysis Using a Nation-Wide Inpatient Database

Perioperative complications and cost of posterior decompression with fusion in thoracic spine for ossification of the posterior longitudinal ligament and ossification of the ligamentum flavum -a comparative study using a national inpatient database

BACKGROUND

Although posterior decompression with fusion (PDF) are effective for treating thoracic myelopathy, surgical treatment has a high risk of various complications. There is currently no information available on the perioperative complications in thoracic ossification of the longitudinal ligament (T-OPLL) and thoracic ossification of the ligamentum flavum (T-OLF). We evaluate the perioperative complication rate and cost between T-OPLL and T-OLF for patients underwent PDF.

METHODS

Patients undergoing PDF for T-OPLL and T-OLF from 2012 to 2018 were detected in Japanese nationwide inpatient database. One-to-one propensity score matching between T-OPLL and T-OLF was performed based on patient characteristics and preoperative comorbidities. We examined systemic and local complication rate, reoperation rate, length of hospital stays, costs, discharge destination, and mortality after matching.

RESULTS

In a total of 2,660 patients, 828 pairs of T-OPLL and T-OLF patients were included after matching. The incidence of systemic complications did not differ significantly between the T-OPLL and OLF groups. However, local complications were more frequently occurred in T-OPLL than in T-OLF groups (11.4% vs. 7.7% P = 0.012). Transfusion rates was also significantly higher in the T-OPLL group (14.1% vs. 9.4%, P = 0.003). T-OPLL group had longer hospital stay (42.2 days vs. 36.2 days, P = 0.004) and higher medical costs (USD 32,805 vs. USD 25,134, P < 0.001). In both T-OPLL and T-OLF, the occurrence of perioperative complications led to longer hospital stay and higher medical costs. While fewer patients in T-OPLL were discharged home (51.6% vs. 65.1%, P < 0.001), patients were transferred to other hospitals more frequently (47.5% vs. 33.5%, P = 0.001).

CONCLUSION

This research identified the perioperative complications of T-OPLL and T-OLF in PDF using a large national database, which revealed that the incidence of local complications was higher in the T-OPLL patients. Perioperative complications resulted in longer hospital stays and higher medical costs.

Comparison of Postoperative Complications and Outcomes in Anterior Cervical Spine Surgery: Ossification of the Posterior Longitudinal Ligament Versus Cervical Spondylotic Myelopathy

STUDY DESIGN

Retrospective cohort study.

OBJECTIVES

To compare the frequency of complications and outcomes between patients with ossification of the posterior longitudinal ligament (OPLL) of the cervical spine and those with cervical spondylotic myelopathy (CSM) who underwent anterior surgery.

SUMMARY OF BACKGROUND DATA

Anterior cervical spine surgery for OPLL is an effective surgical procedure; however, it is complex and technically demanding compared with the procedure for CSM. Few reports have compared postoperative complications and clinical outcomes after anterior surgeries between the 2 pathologies.

METHODS

Among 1434 patients who underwent anterior cervical spine surgery at 3 spine centers within the same spine research group from January 2011 to March 2021, 333 patients with OPLL and 488 patients with CSM were retrospectively evaluated. Demographics, postoperative complications, and outcomes were reviewed by analyzing medical records. In-hospital and postdischarge postoperative complications were investigated. Postoperative outcomes were evaluated 1 year after the surgery using the Japanese Orthopaedic Association score.

RESULTS

Patients with OPLL had more comorbid diabetes mellitus preoperatively than patients with CSM ( P <0.001). Anterior cervical corpectomies were more often performed in patients with OPLL than in those with CSM (73.3% and 14.5%). In-hospital complications, such as reoperation, cerebrospinal fluid leak, C5 palsy, graft complications, hoarseness, and upper airway complications, occurred significantly more often in patients with OPLL. Complications after discharge, such as complications of the graft bone/cage and hoarseness, were significantly more common in patients with OPLL. The recovery rate of the Japanese Orthopaedic Association score 1 year postoperatively was similar between patients with OPLL and those with CSM.

CONCLUSION

The present study demonstrated that complications, both in-hospital and after discharge following anterior spine surgery, occurred more frequently in patients with OPLL than in those with CSM.

Estimated number of spine surgeries and related deaths in Japan from 2014 to 2020

BACKGROUND

The total number of spine surgeries per year and their related deaths in Japan has not been adequately estimated in the literature.

METHODS

We retrospectively reviewed the National Database of Health Insurance Claims and Specific Health Checkups of Japan (NDB) between April 2014 to March 2021, which covers 99.9 % of health insurance claim receipts by general practitioners. The annual number of surgeries was counted using K codes, a procedure classification unique to Japan, and classified into the following six categories; percutaneous vertebroplasty, endoscopic surgery, open discectomy, laminoplasty/laminectomy, instrumentation surgery, and others. The data distribution was also summarized by sex and age. Additionally, by reviewing DPC database-related papers for evaluation of the mortality rate after spine surgery in Japan, the number of spine surgery-related deaths was calculated.

RESULTS

The NDB showed that the number of spine surgeries analyzed in this study increased from 170,081 in 2014 to 193,903 in 2019, with a slight decrease in 2020. The ratio of instrumentation surgery increased from 33.0 % in 2014 to 37.9 % in 2020. The rate of patients aged 75 or older increased 31.6 % to 39.6 %. Combining these findings with DPC data showing a mortality rate of 0.1 % to 0.4 % revealed that the estimated number of deaths related to spine surgery in Japan ranged from 200 to 800 per year.

CONCLUSIONS

Approximately 200,000 spine surgeries and 200 to 800 spine surgery-related inpatient deaths were estimated to have occurred in Japan around 2020.

Kinematic analysis of chewing and swallowing function after cervical spine surgery

PURPOSE

Although movement of the hyoid bone is different for masticatory swallowing and liquid swallowing in normal subjects, it has not been studied after cervical spine surgery. Therefore, we analyzed the swallowing dynamics of masticatory swallowing in anterior cervical spine disease surgery using foods that require chewing close to actual meals.

METHODS

A day before and one week after the surgery, a videofluoroscopic swallow study (VFSS) was performed, and the distance of hyoid bone movement in the anterior and superior directions, amount of opening of the upper esophageal sphincter (UES), time of passage through the pharynx, number of swallows, and amount of pharyngeal residual were measured on the VFSS images during a masticatory swallow of corn flakes. The swallowing function was evaluated by DSS (dysphagia severity scale) and FOIS (functional oral intake scale). Imaging software was used for the measurements.

RESULTS

Postoperative hyoid movement during masticatory swallowing was not significantly different for anterior movement but significantly limited in upward movement (p = 0.002); UES opening volume was significantly decreased (p < 0.001), and bolus residue was significantly worse (p < 0.001), compared to preoperative. The pharyngeal transit time was not significantly different; the number of swallows increased (p < 0.001), along with DSS (p < 0.001) and FOIS (p < 0.001), with significant differences before and after surgery, indicating worsened swallowing function.

CONCLUSIONS

Swallowing function worsened in masticatory swallowing after surgery for cervical spine disease, mainly due to the restriction of upward movement of the hyoid bone and the resulting increase in pharyngeal residuals after swallowing.

Surgical outcomes of robot-assisted radical cystectomy in octogenarian or older patients: A Japanese nationwide study

OBJECTIVE

To evaluate the surgical outcomes of robot-assisted radical cystectomy (RARC) in octogenarian or older patients based on a Japanese nationwide database.

METHODS

The diagnosis procedure combination database was used to extract the data on radical cystectomy cases. Surgical outcomes of RARC in octogenarian or older patients (older group) were initially compared to those of patients younger than 80 years (younger group). Then, the surgical outcomes of RARC in the older group were compared to those of open radical cystectomy (ORC) and laparoscopic radical cystectomy (LRC) in the same age group.

RESULTS

Between 2018 and 2021, 478 RARC cases in the older group and 2257 RARC cases in the younger group were identified. In the older group, ileal conduit, neobladder, and other urinary diversions were carried out in 352 (73.6%), 22 (4.6%), and 104 (21.8%) patients, respectively. In the older group, when compared with the younger group, the complication rate (24.9%), blood transfusion rate (41.4%), and in-hospital mortality (1.4%) were equivalent, while significantly shorter anesthesia time and longer length of stay were observed in the older group (521.0 ± 140.4 min vs. 595.1 ± 141.71 min, p < 0.01, and 32.9 ± 16.8 days vs. 30.6 ± 17.8 days, p = 0.01, respectively). In the comparison of the surgical outcomes of older patients receiving RARC to those receiving ORC (n = 746) and LRC (n = 375), the RARC group had the lowest complication rate and the shortest length of stay, while the shortest anesthesia time was noted in the ORC group.

CONCLUSION

The feasibility of RARC for octogenarian or older patients was demonstrated by the nationwide database study.

Perioperative Complications of Laminoplasty in Degenerative Cervical Myelopathy -A Comparative Study Between Ossification of Posterior Longitudinal Ligament and Cervical Spondylotic Myelopathy Using a Nationwide Inpatient Database

STUDY DESIGN

Retrospective cohort study.

OBJECTIVES

Laminoplasty (LAMP) is one of the effective methods to successfully achieve surgical decompression in patients with degenerative cervical myelopathy (DCM). However, little evidence exists regarding the perioperative complications in LAMP for patients with ossification of the longitudinal ligament (OPLL) compared with cervical spondylotic myelopathy (CSM). We aimed to investigate the perioperative complication rates and medical costs of DCM, including OPLL and CSM patients who underwent LAMP using a large national inpatient database.

METHODS

This study identified patients who underwent LAMP for OPLL and CSM from 2010 to 2016 using the Japanese Diagnosis Procedure Combination database. We compared the incidence of perioperative complications (systemic and local), reoperation rates, medical costs during hospitalization, and mortality were between the OPLL and CSM groups after propensity score matching.

RESULTS

This study included 22,714 patients (OPLL: 7485 patients, CSM: 15,229 patients). Consequently, 7169 pairs were matched. More perioperative systemic complications were detected in the OPLL group (one complication: 9.1% vs 7.7%; P = .002), especially for pneumonia (.5% vs .2%; P = .001) and dysphagia (.5% vs .2%; P = .004). The local complication rate was also higher in the OPLL group (paralysis: 1.1% vs .6%, P = .006; spinal fluid leakage: .4% vs .1%, P = .002). The hospitalization costs were approximately $2300 higher ($19,024 vs $16,770; P < .001) in the OPLL group.

CONCLUSIONS

More perioperative complications and higher medical costs were noted in patients with OPLL than in patients with CSM who underwent LAMP.

Comparison of Surgical Outcomes of Anterior and Posterior Fusion Surgeries for K-line (-) Cervical Ossification of the Posterior Longitudinal Ligament: A Prospective Multicenter Study

STUDY DESIGN

A prospective multicenter study.

OBJECTIVE

The objective of this study is to compare the surgical outcomes of anterior and posterior fusion surgeries in patients with K-line (-) cervical ossification of the posterior longitudinal ligament (OPLL).

SUMMARY OF BACKGROUND DATA

Although laminoplasty is effective for patients with K-line (+) OPLL, fusion surgery is recommended for those with K-line (-) OPLL. However, whether the anterior or posterior approach is preferable for this pathology has not been effectively determined.

MATERIALS AND METHODS

A total of 478 patients with myelopathy due to cervical OPLL from 28 institutions were prospectively registered from 2014 to 2017 and followed up for two years. Of the 478 patients, 45 and 46 with K-line (-) underwent anterior and posterior fusion surgeries, respectively. After adjusting for confounders in baseline characteristics using a propensity score-matched analysis, 54 patients in both the anterior and posterior groups (27 patients each) were evaluated. Clinical outcomes were assessed using the cervical Japanese Orthopaedic Association and the Japanese Orthopaedic Association Cervical Myelopathy Evaluation Questionnaire.

RESULTS

Both approaches showed comparable neurological and functional recovery. The cervical range of motion was significantly restricted in the posterior group because of the large number of fused vertebrae compared with the anterior group. The incidence of surgical complications was comparable between the cohorts, but the posterior group demonstrated a higher frequency of segmental motor paralysis, whereas the anterior group more frequently reported postoperative dysphagia.

CONCLUSIONS

Clinical improvement was comparable between anterior and posterior fusion surgeries for patients with K-line (-) OPLL. The ideal surgical approach should be informed based on the balance between the surgeon's technical preference and the risk of complications.

Residual Neuropathic Pain in Postoperative Patients With Cervical Ossification of Posterior Longitudinal Ligament

STUDY DESIGN

A prospective multi-institutional observational study.

OBJECTIVE

To investigate and identify risk factors for residual neuropathic pain after surgery in patients with cervical ossification of posterior longitudinal ligament (c-OPLL).

SUMMARY OF BACKGROUND DATA

Patients with c-OPLL often require surgery for numbness and paralysis of the extremities; however, postoperative neuropathic pain can considerably deteriorate their quality of life.

METHODS

Out of 479 patients identified from multicenter c-OPLL registries between 2014 and 2017, 292 patients who could be followed up for 2 years postoperatively were reviewed, after excluding patients with nervous system comorbidities. Demographic details; medical history; radiographic factors including the K-line, spinal canal occupancy rate of OPLL, cervical kyphosis angle, and presence of spinal cord myelomalacia; preoperative Japanese Orthopaedic Association (JOA) score; surgical procedure (fusion or decompression surgery); postoperative neurological deterioration; and the visual analogue scale for pain and numbness in the upper extremities (U/E) or trunk/lower extremities (L/E) at baseline and at 2 years postoperatively were assessed. Patients were grouped into residual and non-residual groups based on a postoperative visual analogue scale ≥40 mm. Risk factors for residual neuropathic pain were evaluated by multiple logistic regression analysis.

RESULTS

The prevalence of U/E and L/E residual pain in postoperative c-OPLL patients was 51.7% and 40.4%, respectively. The U/E residual group had a poor preoperative JOA score and longer illness duration, and fusion surgery was more common in the residual group than in non-residual group. The L/E residual group was older with a poorer preoperative JOA score. On multivariate analysis, risk factors for U/E residual pain were long illness duration and poor preoperative JOA score, whereas those for L/E residual pain were age and poor preoperative JOA score.

CONCLUSIONS

The risk factors for residual spinal neuropathic pain after c-OPLL surgery were age, long duration of illness, and poor preoperative JOA score.

LEVEL OF EVIDENCE

IV.

Nationwide sample data analysis of additional surgery rate after anterior or posterior cervical spinal surgery

Surgical outcomes of degenerative cervical spinal disease are dependent on the selection of surgical techniques. Although a standardized decision cannot be made in an actual clinical setting, continued education is provided to standardize the medical practice among surgeons. Therefore, it is necessary to supervise and regularly update overall surgical outcomes. This study aimed to compare the rate of additional surgery between anterior and posterior surgeries for degenerative cervical spinal disease using the National Health Insurance Service-National Sample Cohort (NHIS-NSC) nationwide patient database. The NHIS-NSC is a population-based cohort with about a million participants. This retrospective cohort study included 741 adult patients (> 18 years) who underwent their first cervical spinal surgery for degenerative cervical spinal disease. The median follow-up period was 7.3 years. An event was defined as the registration of any type of cervical spinal surgery during the follow-up period. Event-free survival analysis was used for outcome analysis, and the following factors were used as covariates for adjustment: location of disease, sex, age, type of insurance, disability, type of hospital, Charles comorbidity Index, and osteoporosis. Anterior cervical surgery was selected for 75.0% of the patients, and posterior cervical surgery for the remaining 25.0%. Cervical radiculopathy due to foraminal stenosis, hard disc, or soft disc was the primary diagnosis in 78.0% of the patients, and central spinal stenosis was the primary diagnosis in 22.0% of them. Additional surgery was performed for 5.0% of the patients after anterior cervical surgery and 6.5% of the patients after posterior cervical surgery (adjusted subhazard ratio, 0.83; 95% confidence interval, 0.40-1.74). The rates of additional surgery were not different between anterior and posterior cervical surgeries. The results would be helpful in evaluating current practice as a whole and adjusting the health insurance policy.

Comparison of the outcome after anterior cervical ossified posterior longitudinal ligament en bloc resection versus posterior total laminectomy and fusion in patients with ossification of the cervical posterior longitudinal ligament: a prospective randomized controlled trial

The optimal procedure for the treatment of ossification of the posterior longitudinal ligament (OPLL) remains controversial. The aim of this study was to compare the outcome of anterior cervical ossified posterior longitudinal ligament en bloc resection (ACOE) with posterior laminectomy and fusion with bone graft and internal fixation (PTLF) for the surgical management of patients with this condition. Between July 2017 and July 2019, 40 patients with cervical OPLL were equally randomized to undergo surgery with an ACOE or a PTLF. The clinical and radiological results were compared between the two groups. The Japanese Orthopaedic Association (JOA) score and recovery rate in the ACOE group were significantly higher than those in the PTLF group during two years postoperatively, provided that the canal occupying ratio (COR) was > 50%, or the K-line was negative. There was no significant difference in JOA scores and rate of recovery between the two groups in those in whom the COR was < 50%, or the K-line was positive. There was no significant difference in the Cobb angle between C2 and C7, sagittal vertical axis, cervical range of motion (ROM), and complications between the two groups. Compared with PTLF, ACOE is a preferred surgical approach for the surgical management of patients with cervical OPLL in that it offers a better therapeutic outcome when the COR is > 50%, or the K-line is negative, and it also preserves better cervical curvature and sagittal balance. The prognosis of ACOE is similar to that of PTLE when the COR is < 50%, or the K-line is positive.

Trends of radical cystectomy and comparisons of surgical outcomes among surgical approaches focusing on robot-assisted radical cystectomy: A Japanese nationwide database study

OBJECTIVE

To clarify the trends in radical cystectomy and to compare surgical outcomes among surgical approaches focusing on robot-assisted radical cystectomy based on a Japanese nationwide database.

METHODS

The Diagnosis Procedure Combination database was used to extract data on radical cystectomy cases. Trends in open radical cystectomy, laparoscopic radical cystectomy, minimum incision endoscopic radical cystectomy, and robot-assisted radical cystectomy between April 2012 and March 2021 were evaluated. Basic characteristics and peri-operative indicators were compared among the four groups. Propensity score matching was applied to assess the differences between open radical cystectomy and robot-assisted radical cystectomy.

RESULTS

During the study period, a decreasing number of open radical cystectomies and an increasing number of minimally invasive radical cystectomies were shown in the total cohort of 28 345 cases. The number of robot-assisted radical cystectomies rapidly increased after government approval in 2018. Minimally invasive radical cystectomies, including robot-assisted radical cystectomies, had a significantly lower complication rate, a shorter length of stay, and a lower blood transfusion rate, but a longer anesthesia time than open radical cystectomies. In the propensity score matching analysis comparing the surgical outcomes of robot-assisted radical cystectomy and open radical cystectomy, similar results were demonstrated, and blood transfusion rates were equivalent.

CONCLUSION

For the past decade, the number of minimally invasive radical cystectomies has steadily increased without compromised surgical outcomes, except for anesthesia time. Robot-assisted radical cystectomies in particular rapidly became widespread in Japan after government approval in 2018 and became a standard surgery within the first 3 years.

Prospective Comparative Study of Dysphagia after Subaxial Cervical Spine Surgery: Cervical Spondylotic Myelopathy and Posterior Longitudinal Ligament Ossification

We prospectively investigated the postoperative dysphagia in cervical posterior longitudinal ligament ossification (C-OPLL) and cervical spondylotic myelopathy (CSM) to identify the risk factors of each disease and the incidence. A series of 55 cases with C-OPLL: 13 anterior decompression with fusion (ADF), 16 posterior decompression with fusion (PDF), and 26 laminoplasty (LAMP), and a series of 123 cases with CSM: 61 ADF, 5 PDF, and 57 LAMP, were included. Vertebral level, number of segments, approach, and with or without fusion, and pre and postoperative values of Bazaz dysphagia score, C2-7 lordotic angle (&ang;C2-7), cervical range of motion, O-C2 lordotic angle, cervical Japanese Orthopedic Association score, and visual analog scale for neck pain were investigated. New dysphagia was defined as an increase in the Bazaz dysphagia score by one grade or more than one year after surgery. New dysphagia occurred in 12 cases with C-OPLL; 6 with ADF (46.2%), 4 with PDF (25%), 2 with LAMP (7.7%), and in 19 cases with CSM; 15 with ADF (24.6%), 1 with PDF (20%), and 3 with LAMP (1.8%). There was no significant difference in the incidence between the two diseases. Multivariate analysis demonstrated that increased &ang;C2-7 was a risk factor for both diseases.

Prospective Investigation of Surgical Outcomes after Anterior Decompression with Fusion and Laminoplasty for the Cervical Ossification of the Posterior Longitudinal Ligament: A Propensity Score Matching Analysis

The ideal surgical strategy for cervical ossification of the posterior longitudinal ligament (OPLL) remains controversial due to the lack of high-quality evidence. Herein, we prospectively investigated the surgical outcomes of anterior cervical decompression with fusion (ADF) and laminoplasty (LAMP) with cervical OPLL. Three hundred patients were included in this study (ADF: n = 89; LAMP: n = 211 patients), and propensity score matching yielded 67 pairs of patients with ADF and LAMP, in which clinical outcomes were compared. Crude analysis revealed that the ADF group showed greater neurological recovery in cervical Japanese Orthopedic Association scores at two years, compared with that in the LAMP group (53.1% vs. 44.3%, p = 0.037). The ratio of minimum clinically important difference (MCID) success was significantly greater in the ADF group (59.6% vs. 43.6%, p = 0.016). Multivariate analysis showed that the factors affecting MCID success were age, body mass index, duration of symptoms, and choice of ADF. In the 1:1 matched analysis, neurological improvement was more favorable in the ADF group (57.2%) compared to the LAMP group (46.8%) at two years (p = 0.049). However, perioperative complications, such as dysphagia and graft-related complications, were more common in the ADF group.

Perioperative Complications of Anterior Decompression with Fusion in Degenerative Cervical Myelopathy-A Comparative Study between Ossification of Posterior Longitudinal Ligament and Cervical Spondylotic Myelopathy Using a Nationwide Inpatient Database

For ossification of the posterior longitudinal ligament (OPLL) and cervical spondylotic myelopathy (CSM), anterior decompression with fusion (ADF) can accurately achieve spinal decompression. However, the difference in perioperative complications in ADF between OPLL and CSM is poorly described. This study aimed to investigate the perioperative complication rates of patients with degenerative cervical myelopathy undergoing ADF, represented by OPLL and CSM, using a large national inpatient database. In the OPLL and CSM groups, postoperative complication (systemic and local) rates, reoperation rates, medical costs during hospitalization, and mortality after propensity score matching were compared. After matching, 1197 matched pairs were made. The incidence of total systemic complications was similar between both groups (OPLL, 12.4%; CSM, 12.2%). In the OPLL group, more perioperative local complications (cerebrospinal fluid leakage: CSFL, [OPLL, 2.7%; CSM, 0.3%] and surgical site infection: SSI [OPLL, 2.1%; CSM, 0.9%]) were detected, and the hospitalization cost was approximately $3200 higher than that in the CSM group. Moreover, medical costs were significantly higher in patients who experienced complications in both OPLL and CSM. The frequency of perioperative complications of OPLL and CSM in ADF was detailed using large real-world data. Compared to CSM, OPLL had more perioperative complications such as CSFL and SSI, and higher medical costs. Regardless of the disease, medical costs were significantly increased when perioperative complications occurred.

MRI T2WI High Signal Is a Risk Factor for Perioperative Complications in Patients with Cervical Spondylosis with Spinal Cord Compression: A Propensity Matching Score Analysis

Objective

The purpose of this study was to compare the perioperative complications and clinical efficacy of patients with cervical spondylosis with spinal cord compression (CSWSCC) with or without MRI T2WIHS (T2-weighted image high signal) by means of propensity matching score grouping.

Methods

We analyzed a single-center data of 913 surgical patients with CSWSCC by propensity matching score in this study, of which 326 patients had preoperative cervical MRI T2WIHS. The patient's general condition and perioperative indicators were collected. The MRI T2WIHS and normal groups were paired 1 : 1 to eliminate selection bias by propensity matching score. Finally, a total of 312 pairs were matched successfully. The results of perioperative complications and other outcome variables were compared between the two groups by Cox function analysis.

Results

The postoperative blood loss, operation time, blood transfusion volume, systemic complications, local complications, volume of drainage, abnormal use of antibiotic, length of hospital stay, and JOA (Japanese Orthopaedic Association) improvement rate were analyzed. As the only complication with significant statistical difference, the incidence of IRI (ischemia-reperfusion injury) in patients with MRI T2WIHS was significantly higher. The length of hospital stay was more significantly increased in patients with MRI T2WIHS; on the contrary, the JOA improvement rate decreased significantly.

Conclusion

This study confirmed that there was no significant difference in the incidence of perioperative complications in CSWSCC patients with or without MRI T2WIHS, except for the IRI. Moreover, the JOA improvement rate of patients without MRI T2WIHS was significantly better, with the length of hospital stay reduced.

Severity of Myelopathy is Closely Associated With Advanced Age and Signal Intensity Change in Cervical Ossification of the Posterior Longitudinal Ligament: A Prospective Nationwide Investigation

STUDY DESIGN

Prospective, nationwide case series.

OBJECTIVE

To identify preoperative factors associated with myelopathy and neurological impairment in patients with cervical ossification of the posterior longitudinal ligament (OPLL).

SUMMARY OF BACKGROUND DATA

Various studies have reported clinical outcomes following the surgical treatment of OPLL. However, there has been no large-scale study of preoperative clinical features in patients with cervical OPLL.

MATERIALS AND METHODS

Data were prospectively collected from 28 institutions nationwide in Japan. In total, 512 patients with neurological impairment caused by cervical OPLL requiring surgery were enrolled. Basic demographic and clinical data, including age, sex, diabetes status, body mass index, smoking history, and disease duration were collected. C2-7 lordotic angle, canal narrowing ratio, range of motion in flexion-extension at C2-7, and type of OPLL were evaluated on lateral radiographs to identify factors influencing the clinical features of patients with OPLL in whom surgery was planned.

RESULTS

Complete documentation was available for 490 patients (362 male, 128 female). In total, 34 patients had the localized type, 181 had the segmental type, 64 had the continuous type, and 211 had the mixed type. Although there were no significant differences in age, body mass index, disease duration, Japanese Orthopedic Association (JOA) score, and lordotic angle at C2-7 according to the type of OPLL, significant differences were observed in a range of motion at C2-7 and the canal narrowing ratio among the 4 types. Multiple regression analysis revealed that the JOA score was significantly associated with age and signal intensity change on magnetic resonance imaging.

CONCLUSIONS

This is the first large-scale, prospective, multicenter case series study to investigate factors influencing preoperative neurological status in patients with OPLL. Age and signal intensity change on magnetic resonance images were significantly associated with JOA score in patients requiring surgery.

LEVEL OF EVIDENCE

Level II.

Efficacy of Intraoperative Neuromonitoring Using Transcranial Motor-Evoked Potentials for Degenerative Cervical Myelopathy: A Prospective Multicenter Study by the Monitoring Committee of the Japanese Society for Spine Surgery and Related Research

STUDY DESIGN

A prospective multicenter observational study.

OBJECTIVE

To elucidate the efficacy of transcranial motor-evoked potentials (Tc(E)-MEPs) in degenerative cervical myelopathy (DCM) surgery by comparing cervical spondylotic myelopathy (CSM) to cervical ossification of the posterior longitudinal ligament (OPLL) and investigate the timing of Tc(E)-MEPs alerts and types of interventions affecting surgical outcomes.

SUMMARY OF BACKGROUND DATA

Although CSM and OPLL are the most commonly encountered diseases of DCM, the benefits of Tc(E)-MEPs for DCM remain unclear and comparisons of these two diseases have not yet been conducted.

METHODS

We examined the results of Tc(E)-MEPs from 1176 DCM cases (840 CSM /336 OPLL) and compared patients background by disease, preoperative motor deficits, and the type of surgical procedure. We also assessed the efficacy of interventions based on Tc(E)-MEPs alerts. Tc(E)-MEPs alerts were defined as an amplitude reduction of more than 70% below the control waveform. Rescue cases were defined as those in which waveform recovery was achieved after interventions in response to alerts and no postoperative paralysis.

RESULTS

Overall sensitivity was 57.1%, and sensitivity was higher with OPLL (71.4%) than with CSM (42.9%). The sensitivity of acute onset segmental palsy including C5 palsy was 40% (OPLL/CSM: 66.7%/0%) whereas that of lower limb palsy was 100%. The most common timing of Tc(E)-MEPs alerts was during decompression (63.16%), followed by screw insertion (15.79%). The overall rescue rate was 57.9% (OPLL/CSM: 58.3%/57.1%).

CONCLUSION

Since Tc(E)-MEPs are excellent for detecting long tract injuries, surgeons need to consider appropriate interventions in response to alerts. The detection of acute onset segmental palsy by Tc(E)-MEPs was partially possible with OPLL, but may still be difficult with CSM. The rescue rate was higher than 50% and appropriate interventions may have prevented postoperative neurological complications.Level of Evidence: 3.

Perioperative Complications in Posterior Surgeries for Cervical Ossification of the Posterior Longitudinal Ligament: A Prospective Nationwide Investigation

STUDY DESIGN

This was a prospective multicenter study.

OBJECTIVE

The aim of this study was to investigate the perioperative complications of posterior surgeries for the treatment of cervical ossification of the posterior longitudinal ligament (OPLL).

SUMMARY OF BACKGROUND DATA

Surgical treatment for cervical OPLL has a high risk of various complications. Laminoplasty (LAMP) and posterior decompression and instrumented fusion (PDF) are effective for multilevel cervical OPLL; however, few studies have focused on the surgical complications of these 2 procedures.

MATERIALS AND METHODS

We prospectively included 380 patients undergoing posterior surgeries for cervical OPLL (LAMP: 270 patients, PDF: 110 patients), and investigated the systemic and local complications, including neurological complications. We further evaluated risk factors related to the neurological complications.

RESULTS

Motor palsy was found in 40 patients (10.5%), and motor palsy in the upper extremity was most frequent (8.9%), especially in patients who received PDF (14.5%). Motor palsies involving the lower extremities was found in 6 patients (1.6%). Regarding local complications, dural tears (3.9%) and surgical site infections (2.6%) were common. In the univariate analysis, body mass index, preoperative cervical alignment, fusion surgery, and the number of operated segments were the factors related to motor palsy. Multivariate analysis revealed that fusion surgery and a small preoperative C2-C7 angle were the independent factors related to motor palsy. Motor palsy involving the lower extremities tended to be found at early time points after the surgery, and all the patients fully recovered. Motor palsy in the upper extremities occurred in a delayed manner, and 68.8% of patients with PDF showed good recovery, whereas 81.3% of patients with LAMP showed good recovery.

CONCLUSIONS

In posterior surgeries for cervical OPLL, segmental motor palsy in the upper extremity was most frequently observed, especially in patients who received PDF. Fusion and a small preoperative C2-C7 angle were the independent risk factors for motor palsy.

LEVEL OF EVIDENCE

Level III.

Association between Severity of Diffuse Idiopathic Skeletal Hyperostosis and Ossification of Other Spinal Ligaments in Patients with Ossification of the Posterior Longitudinal Ligament

Background: Although diffuse idiopathic skeletal hyperostosis (DISH) is known to coexist with the ossification of spinal ligaments (OSLs), details of the radiographic relationship remain unclear. Methods: We prospectively collected data of 239 patients with symptomatic cervical ossification of the posterior longitudinal ligament (OPLL) and analyzed the DISH severity on whole-spine computed tomography images, using the following grades: grade 0, no DISH; grade 1, DISH at T3–T10; grade 2, DISH at both T3–T10 and C6–T2 and/or T11–L2; and grade 3, DISH beyond C5 and/or L3. Ossification indices were calculated as the sum of vertebral and intervertebral levels with OSL for each patient. Results: DISH was found in 107 patients (44.8%), 65 (60.7%) of whom had grade 2 DISH. We found significant associations of DISH grade with the indices for cervical OPLL (r = 0.45, p < 0.0001), thoracic ossification of the ligamentum flavum (OLF; r = 0.41, p < 0.0001) and thoracic ossification of the supra/interspinous ligaments (OSIL; r = 0.53, p < 0.0001). DISH grade was also correlated with the index for each OSL in the whole spine (OPLL: r = 0.29, p < 0.0001; OLF: r = 0.40, p < 0.0001; OSIL: r = 0.50, p < 0.0001). Conclusion: The DISH grade correlated with the indices of OSL at each high-prevalence level as well as the whole spine.

Trends and safety of robot-assisted partial nephrectomy during the initial 2-year period after government approval in Japan: A nationwide database study from 2016 to 2018

OBJECTIVES

To evaluate the trends and safety of robot-assisted partial nephrectomy during the initial 2-year period after government approval for this type of procedure in April 2016.

METHODS

This nationwide retrospective study included 3722 received robot-assisted partial nephrectomy cases carried out from April 2016 to March 2018 in 124 participating institutions. The institutions were divided into lower- and higher-volume institutions according to the median of 19 robot-assisted partial nephrectomy cases during the study period. Surgical outcomes between 616 cases from lower-volume institutions and 3106 cases from higher-volume institutions were compared using propensity score matching.

RESULTS

During the study period, both the number of robot-assisted partial nephrectomy surgeries and the number of institutions in which the surgery was carried out steadily increased. Overall, the median anesthesia time was 217 min, the median postoperative length of stay was 9 days, and the proportion of blood transfusions, complications and readmissions were 0.8%, 5.1% and 1.0%, respectively. There were no significant differences in anesthesia time, incidence of blood transfusions, and complication rates between the lower-volume and higher-volume institutions. However, a slightly, but significantly, longer postoperative length of stay and a lower incidence of readmission were observed in lower-volume institutions both before and after propensity score matching.

CONCLUSIONS

Robot-assisted partial nephrectomy has become widespread during the initial 2-year period after government approval with an acceptable safety profile, regardless of the institutional caseloads. This technique has become a standard of care for stage 1 renal cancer patients in Japan.

Impact of Diabetes Mellitus on Cervical Spine Surgery for Ossification of the Posterior Longitudinal Ligament

Ossification of the posterior longitudinal ligament (OPLL) is commonly associated with diabetes mellitus (DM); however, the impact of DM on cervical spine surgery for OPLL remains unclear. This study was performed to evaluate the influence of diabetes DM on the outcomes following cervical spine surgery for OPLL. In total, 478 patients with cervical OPLL who underwent surgical treatment were prospectively recruited from April 2015 to July 2017. Functional measurements were conducted at baseline and at 6 months, 1 year, and 2 years after surgery using JOA and JOACMEQ scores. The incidence of postoperative complications was categorized into early (≤30 days) and late (>30 days), depending on the time from surgery. From the initial group of 478 patients, 402 completed the 2-year follow-up and were included in the analysis. Of the 402 patients, 127 (32%) had DM as a comorbid disease. The overall incidence of postoperative complications was significantly higher in patients with DM than in patients without DM in both the early and late postoperative periods. The patients with DM had a significantly lower JOA score and JOACMEQ scores in the domains of lower extremity function and quality of life than those without DM at the 2-year follow-up.

Modified axial computed tomography classification of cervical ossification of the posterior longitudinal ligament: selecting the optimal operating procedure and enhancing the accuracy of prognosis

Background

Cervical ossification of the posterior longitudinal ligament (OPLL) causes spinal cord compression, which can lead to myelopathy or radiculopathy. Non-surgical treatments have little effect on this condition. Current OPLL classification systems offer little guidance on the selection of an appropriate operating procedure. In this study, we developed a modified axial computed tomography classification (MACTC) scheme. We then examined the usefulness of the MACTC scheme and two other existing classification schemes in guiding OPLL operation choice.

Methods

Following screening in which a defined exclusion criteria was used, a total of 91 patients with OPLL participated in the study. Patients' follow-up data for at least 2 years were obtained. The recovery rate of the Japanese Orthopaedic Association (JOA) scores was compared to two other classification schemes.

Results

According to the MACTC, central-sharp-type OPLL had a lower recovery rate of the JOA score than that of central-gentle-type OPLL (36.05±32.38 vs. 83.90±23.52, P≤0.05). The recovery rate of the JOA scores in the ipsilateral open-door OPLL group was significantly lower than that in the contralateral group of the lateral-steep type (36.67±41.5 vs. 88.89±17.21, P=0.04), but not of that in the lateral-gentle type. There was no significant difference in the recovery rates of the JOA scores between groups when using either existing classification scheme (P>0.05).

Conclusions

The MACTC scheme can assist surgeons to choose the most appropriate operating procedure, and provide an accurate prognosis. If operations on central-sharp-type OPLL are not performed using both the posterior and anterior approaches, prognosis will be poor. The contralateral side should be the first choice for door opening in laminoplasty, especially for patients with lateral-steep-type OPLL. Severe OPLL may not be an absolute contraindication for the posterior approach.

Risk Factors and Assessment Using an Endoscopic Scoring System for Postoperative Respiratory Complications after Anterior Cervical Decompression and Fusion Surgery

Introduction

Postoperative respiratory complications (PRC) are one of the most serious complications. Potentially life-threatening accidents can occur after an anterior cervical discectomy and fusion (ADF), such as airway obstruction and aspiration pneumonia. Despite numerous studies, preoperative predictive and preventive methodology has yet to be established.

As reported in our previous study, the evaluation of preoperative dysphagia using the eating assessment tool (EAT-10) and a flexible endoscopic evaluation of swallowing (FEES) is useful for predicting the incidence and risk factors of dysphagia after ADF.

Methods

This prospective study comprised 60 consecutive patients who underwent ADF. An otolaryngologist and a speech-language-hearing therapist preoperatively and 1 week postoperatively evaluated dysphagia using EAT-10 and Hyodo-Komagane (H-K) scores during FEES. Patient demographics, comorbidities, and pre- and postoperative dysphagia were compared between patients with and without PRC.

Results

Seven of 60 (11.6%) patients had preoperative dysphagia diagnosed using the H-K score. A significant positive correlation existed between the pre- and postoperative H-K scores. Of all 60 cases, eight (13.3%) had PRC. Among them, two required reintubation due to airway obstruction and six had aspiration pneumonia. The PRC(+) group was significantly older and more prone to diabetes and asthma. The preoperative H-K score of the PRC(+) group was significantly higher than that of the PRC(−) group. Postoperatively, but not preoperatively, EAT-10 was significantly higher in the PRC(+) group.

Conclusions

Preoperative dysphagia may potentially exacerbate postoperative dysphagia after ADF. A preoperative evaluation of dysphagia using the H-K score during FEES is a useful method for predicting and reducing the risk of PRC.

Level of Evidence: 3