Perioperative complications of anterior decompression with fusion versus laminoplasty for the treatment of cervical ossification of the posterior longitudinal ligament: propensity score matching analysis using a nation-wide inpatient database

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.

Risk Factors for Cerebrospinal Fluid Leakage After Extradural Spine Surgery: A Meta-Analysis and Systematic Review

BACKGROUND

Cerebrospinal fluid (CSF) leakage is 1 of the common complications of spine surgery and is largely caused by intraoperative or postoperative dural tears. Associations of different factors with postoperative CSF leakage have not been consistent. In this study we aimed to identify demographic, disease-related, and surgical risk factors for CSF leakage after extradural spine surgery in a systematic review and meta-anlysis.

METHODS

The PubMed, EMBASE, Web of Science, Cochrane Library, Chinese National Knowledge Infrastructure, Chinese Wanfang data, Chinese Weipu Database, and SinoMed databases were searched from inception until October 24, 2022. Fixed-effects or random-effects models were used to calculate odds ratios and 95% confidence intervals. The quality of observational studies was evaluated using the Newcastle-Ottawa scale instrument.

RESULTS

A total of 15 observational studies with 1,719,923 participants were included in this systematic review. All studies had a Newcastle-Ottawa scale score greater than or equal to 6. Age older than 70 years, smoking, ossification of the posterior longitudinal ligament, adhesion of spinal dura, spinal canal stenosis, cervical fracture, spondylolisthesis, revision surgery, and multiple surgical segments were all related to CSF leakage in the pooled analysis. Obesity and disease duration>1 year were not associated with the leakage of CSF.

CONCLUSIONS

This study will provide a reference for the identification of patients at high risk of developing CSF leakage, which suggests clinicians to strengthen the observation of drainage fluid in high-risk groups.

Incidence and risk factors of surgical site infection following cervical laminoplasty: A retrospective clinical study

There are many debates regarding the risk factors of surgical site infection (SSI) following posterior cervical surgery in previous studies. And, till now there is no such a study to examine cervical laminoplasty surgery. From January 2011 through October 2021, a total of 405 patients who were treated with unilateral open-door laminoplasty surgeries were enrolled in this study. We divided the patients into the SSI group and the non-SSI group and compared their patient-specific and procedure-specific factors. Univariate and multiple logistic regression analysis were performed to determine the risk factors. Of the 405 patients, 20 patients had SSI. The rate of SSI found to be 4.93%. There were significant differences between groups in the thicker subcutaneous fat thickness (FT) (p < 0.001), the higher ratio of subcutaneous FT to muscle thickness (MT) (p < 0.001), the higher preoperative Japanese Orthopaedic Association (JOA) Scores (p < 0.003), the decreased preoperative serum albumin (p < 0.001), the more postoperative drainage (p < 0.05) and the longer time of draining (p < 0.001). Logistic regression analysis of these differences showed that the higher ratio of subcutaneous FT/MT, the higher preoperative JOA scores, the decreased preoperative serum albumin and the longer time of draining were significantly related to SSI (p < 0.05). The higher ratio of subcutaneous FT/MT, the higher preoperative JOA scores, the decreased preoperative serum albumin and the longer time of draining are identified as the independent risk factors of SSI in cervical laminoplasty. Identification of these risk factors could be useful in reducing the SSI incidence and patients counselling.

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.

Augmented Reality Support for Anterior Decompression and Fusion Using Floating Method for Cervical Ossification of the Posterior Longitudinal Ligament

Anterior decompression and fusion (ADF) using the floating method for cervical ossification of the posterior longitudinal ligament (OPLL) is an ideal surgical technique, but it has a specific risk of insufficient decompression caused by the impingement of residual ossification. Augmented reality (AR) support is a novel technology that enables the superimposition of images onto the view of a surgical field. AR technology was applied to ADF for cervical OPLL to facilitate intraoperative anatomical orientation and OPLL identification. In total, 14 patients with cervical OPLL underwent ADF with microscopic AR support. The outline of the OPLL and the bilateral vertebral arteries was marked after intraoperative CT, and the reconstructed 3D image data were transferred and linked to the microscope. The AR microscopic view enabled us to visualize the ossification outline, which could not be seen directly in the surgical field, and allowed sufficient decompression of the ossification. Neurological disturbances were improved in all patients. No cases of serious complications, such as major intraoperative bleeding or reoperation due to the postoperative impingement of the floating OPLL, were registered. To our knowledge, this is the first report of the introduction of microscopic AR into ADF using the floating method for cervical OPLL with favorable clinical results.

Analysis of swallowing function after anterior/posterior surgery for cervical degenerative disorders and factors related to the occurrence of postoperative dysphagia

BACKGROUND CONTEXT

Dysphagia is one of the postoperative complications of cervical degenerative disorders. However, few studies have evaluated the pre- and postoperative swallowing function in detail.

PURPOSE

To analyze pre- and postoperative swallowing dynamics kinetically and investigate factors associated with postoperative dysphagia in patients with cervical degenerative disorders.

STUDY DESIGN

Retrospective review of prospectively collected data.

PATIENT SAMPLE

A total of 41 consecutive patients who underwent an anterior approach (anterior cervical discectomy/corpectomy and fusion (ACDF, ACCF), hybrid surgery (ACDF+ACCF) and total disc replacement) and 44 consecutive patients who underwent a posterior approach (laminoplasty and laminoplasty/laminectomy with fusion).

OUTCOME MEASURES

We compared the pre- and postoperative functional oral intake scale (FOIS), dysphagia severity scale (DSS), esophageal dysphagia, anterior/superior hyoid movement, upper esophageal sphincter (UES) opening, pharyngeal transit time, bolus residue scale (BRS), and the number of swallows.

METHODS

Videofluoroscopy was performed on the day before surgery and within two weeks after surgery. Data related to age, gender, disease, surgical procedure, surgical site, operative time, and blood loss were collected from the medical records. Pre- and postoperative data were compared for each item in the anterior and posterior approaches. The odds ratio of dysphagia after an anterior approach was also calculated.

RESULTS

In the anterior approach, DSS, FOIS, the anterior and superior hyoid movements, maximum UES opening, BRS, and number of swallows worsened postoperatively (p<.05, respectively). In the posterior approach, DSS, FOIS, the anterior hyoid movement, and BRS worsened postoperatively (p<.05, respectively). The factors associated with dysphagia were a proximal surgical site above C3 (OR: 14.40, CI: 2.84-73.02), blood loss >100 mL (OR: 9.60, CI: 2.06-44.74), an operative time >200 minutes (OR: 8.18, CI: 1.51-44.49), and an extensive surgical field of more than three intervertebral levels (OR: 6.72, CI: 1.50-30.07). The decline in swallowing function after the posterior approach was related to aging (p=.045).

CONCLUSIONS

Each approach may decrease swallowing function, especially because of the limitation on the anterior hyoid movement. Dysphagia after anterior approaches was associated with the operative site, operative time, and blood loss.

What Is the Impact of Surgical Approach in the Treatment of Degenerative Cervical Myelopathy in Patients With OPLL? A Propensity-Score Matched, Multi-Center Analysis on Inpatient and Post-Discharge 90-Day Outcomes

STUDY DESIGN

Retrospective cohort.

OBJECTIVE

Provide a comparison of surgical approach in the treatment of degenerative cervical myelopathy in patients with OPLL.

METHODS

A national database was queried to identify adult (≥18 years) patients with OPLL, who underwent at least a 2-level cervical decompression and fusion for cervical myelopathy from 2012-2014. A propensity-score-matching algorithm was employed to compare outcomes by surgical approach.

RESULTS

After propensity-score matching, 627 patients remained. An anterior approach was found to be an independent predictor for higher inpatient surgical complications(OR 5.9), which included dysphagia:14%[anterior]vs.1.1%[posterior] P-value < 0.001, wound hematoma:1.7%[anterior]vs.0%[posterior] P-value = 0.02, and dural tear:9.4%[anterior]vs.3.2%[posterior] P-value = 0.001. A posterior approach was an predictor for longer hospital length of stay by nearly 3 days(OR 3.4; 6.8 days[posterior]vs.4.0 days[anterior] P-value < 0.001). The reasons for readmission/reoperation did not vary by approach for 2-3-level fusions; however, for >3-level fusions, patients with an anterior approach more often had respiratory complications requiring mechanical ventilation(P-value = 0.038) and required revision fusion surgery(P-value = 0.015).

CONCLUSIONS

The national estimates for inpatient complications(25%), readmissions(9.9%), and reoperations(3.5%) are substantial after the surgical treatment of multi-level OPLL. An anterior approach resulted in significantly higher inpatient surgical complications, but this did not result in a longer hospital length of stay and the overall 90-day complication rates requiring readmission or reoperation was similar to those seen after a posterior approach. For patients requiring >3-level fusion, an anterior approach is associated with significantly higher risk for respiratory complications requiring mechanical ventilation and revision fusion surgery. Precise neurological complications and functional outcomes were not included in this database, and should be further assessed in future studies.

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.

Impact of obesity on cervical ossification of the posterior longitudinal ligament: a nationwide prospective study

Positive association between ossification of the posterior longitudinal ligament of the spine (OPLL) and obesity is widely recognized; however, few studies focused on the effects of obesity on treatment of cervical OPLL. The effects of obesity on surgical treatment of cervical OPLL were investigated by a Japanese nationwide, prospective study. Overall, 478 patients with cervical myelopathy due to OPLL were prospectively enrolled. To clarify the effects of obesity on the surgical treatment for cervical OPLL, patients were stratified into two groups, non-obese (< BMI 30.0 kg/m²) and obese (≥ BMI 30.0 kg/m²) groups. The mean age of the obese group was significantly younger than that of non-obese group. There were no significant differences between the two groups in other demographic information, medical history, and clinical and radiographical findings. Alternatively, the obese group had a significantly higher rate of surgical site infection (SSI) than that of non-obese group. Approach-specific analyses revealed that the SSI was significantly higher in the obese group than in the non-obese group. A logistic regression analysis revealed that age, BMI, and duration of symptoms were significant factors affecting the postoperative minimum clinically important difference success. The result of this study provides useful information for future cervical OPLL treatment.

Comparison of perioperative complications in anterior decompression with fusion and posterior decompression with fusion for thoracic ossification of the posterior longitudinal ligament -a retrospective cohort study using a nationwide inpatient database

BACKGROUND

Thoracic ossification of the posterior longitudinal ligament (T-OPLL) is a rare disease, which can cause spinal cord compression leading to various neurological symptoms. There are limited treatment options for T-OPLL, surgery is generally considered the only effective treatment. However, few studies have investigated surgical complications in patients with T-OPLL, and there are no data regarding surgical risks in anterior decompression with fusion (ADF) when compared with posterior decompression with fusion (PDF) for T-OPLL.

METHODS

Patients who were diagnosed as T-OPLL and underwent ADF via the anterior approach and PDF via the posterior approach from April 1, 2012 to March 31, 2018, were extracted from the Diagnosis Procedure Combination (DPC) database. We analyzed perioperative systemic and local complication rates after ADF and PDF and compared them using propensity score matching (PSM) method. In each of the two groups, we investigated the details of length of stay, costs, mortality, and discharge destination.

RESULTS

In total 1344 patients (ADF: 88 patients, PDF: 1256 patients), 176 patients were investigated after PSM (88 pairs). While the incidence of overall systemic complication was significantly higher in the ADF group (ADF/PDF: 25.0%/8.0%, P = 0.002), there was no significant difference in the overall local complication rate (15.9%/19.3%, P = 0.55). Specifically, respiratory complications were more frequently observed in the ADF group (9.1%/0%, P = 0.004), however, other systemic and local complications did not differ significantly between the two groups. The length of stay was 1.7 times longer (P < 0.001) and the medical costs were 1.4 times higher (P < 0.001) in patients with perioperative complications, compared to those without perioperative complications.

CONCLUSION

We demonstrated the perioperative complications of ADF and PDF in patients with T-OPLL using a large national database. ADF showed a higher incidence of respiratory complications. Development of perioperative complications was associated with longer hospital stay and higher medical costs.

Prospective Investigation of Postoperative Complications in Anterior Decompression with Fusion for Severe Cervical Ossification of the Posterior Longitudinal Ligament: A Multi-institutional Study

STUDY DESIGN

A prospective multicenter study.

OBJECTIVE

This study aims to investigate the postoperative complications of anterior decompression with fusion (ADF) 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. ADF is reported to be effective for cervical OPLL, especially for massive OPLL. However, few studies have focused on the surgical complications of ADF.

METHODS

We prospectively included 102 patients undergoing ADF for severe cervical OPLL with average canal occupying ratio of 49.8%. We evaluated systemic and local complications, neurological complications, and risk factors related to the postoperative complications.

RESULTS

Frequently observed complications included graft/ implant complications (18.6%), neurological complications (11.8%), and cerebrospinal fluid leak (11.8%). Motor palsy involving only the upper extremity was found in nine patients (8.8%), and other motor palsies involving the lower extremities were found in three patients (2.9%). None of the preoperative factors were significantly associated with the occurrence of neurological palsies, whereas the number of operated levels was a significant factor related to the postoperative graft/implant complications (P = 0.003; odds ratio, 2.112). The incidence of graft/implant complications and related reoperation increased as the number of operated levels increased (especially four levels or more). Most motor palsies were observed immediately after surgery. Of the motor palsies in the bilateral upper extremities and palsies involving the lower extremities, 85.7% showed good recovery, whereas only 40% of unilateral upper extremity motor palsies showed good recovery during the follow-up period.

CONCLUSION

In ADF for cervical OPLL, the number of operated levels was a significant factor related to the postoperative complication. Specifically, the incidence of graft/implant complications and reoperation rate increased in ADF with four or more levels.Level of Evidence: 3.

Clinical outcomes of laminoplasty for patients with lysosomal storage disease including mucopolysaccharidosis and mucolipidoses: a retrospective cohort study

Background

Although the clinical efficacy of laminoplasty in adult cervical spondylotic myelopathy or ossification of posterior longitudinal ligament has been frequently reported, there are only few reports of laminoplasty for patients with lysosome storage diseases (LSDs). Therefore, this study aimed to report the midterm clinical and radiological outcomes of patients with LSDs after cervical laminoplasty.

Methods

Six patients with LSD who underwent laminoplasty with/without C1 laminectomy for cervical myelopathy were enrolled. Clinical evaluations, including the cervical Japanese Orthopedic Association (cJOA) score and visual analog scale (VAS) scores for upper extremity numbness, and radiographic parameters, including C2–C7 lordotic angle, atlanto-dens interval (ADI), and ⊿ADI, were evaluated preoperatively, at 2 years postoperatively, and at the final follow-up.

Results

Five patients had mucopolysaccharidoses (type I: n = 1, II: n = 3, VII: n = 1) and one patient had mucolipidoses type III. The mean age of patients at surgery was 27.5 years, and the mean postoperative follow-up period was 61 months. All mucopolysaccharidoses cases required C1 posterior arch resection with C2–C7 laminoplasty. No critical complications were observed postoperatively. There were no significant differences in C2–C7 angle (p = 0.724) and ⊿ADI (p = 0.592) between the preoperative and final follow-ups. The cJOA score and VAS for numbness significantly improved at the final follow-up (p = 0.004 and p = 0.007, respectively).

Conclusions

The cervical myelopathy in patients with LSD could be safely and effectively treated with laminoplasty with/without C1 posterior arch resection after excluding patients with atlantoaxial instability. Atlantoaxial stability and symptom improvement could be maintained at an average of 5 years postoperatively.

Comparison of Interventions for Cervical Ossification of Posterior Longitudinal Ligament: A Systematic Review and Network Meta-Analysis

OBJECTIVE

To summarize the literature and systematically evaluate outcomes for ossification of posterior longitudinal ligament interventions including anterior cervical corpectomy and fusion (ACCF), anterior controllable antedisplacement and fusion (ACAF), laminoplasty (LP), and laminectomy with fusion (LF).

METHODS

We searched PubMed, Embase, Web of Science, and the Cochrane Library from January 1990 to March 2021. Patient demographic data, Japanese Orthopaedic Association score, cervical lordosis and overall complications were analyzed.

RESULTS

We evaluated 30 studies involving 2038 patients. Patients undergoing ACCF had improved Japanese Orthopaedic Association scores compared with patients undergoing LP (weighted mean difference [WMD] 1.17, 95% confidence interval [CI] 0.49-1.85) and LF (WMD 1.21, 95% CI 0.17-2.24). Patients with ACAF had better cervical lordosis compared with patients with ACCF (WMD 7.00, 95% CI 0.72-13.27), LP (WMD 10.27, 95% CI 4.64-15.90), and LF (WMD 8.98, 95% CI 2.48-15.47). Additionally, ACAF (odds ratio 0.24, 95% CI 0.07-0.84) and LP (odds ratio 0.50, 95% CI 0.28-0.90) had a lower incidence of complications compared with ACCF.

CONCLUSIONS

Japanese Orthopaedic Association score outcomes indicated that ACCF was superior to LP and LF. ACAF had the largest cervical lordosis among all procedures. ACCF showed a higher incidence of overall complications compared with ACAF and LP.

Comparison of Perioperative Complications in Anterior Decompression With Fusion and Posterior Decompression With Fusion for Cervical Spondylotic Myelopathy: Propensity Score Matching Analysis Using a Nationwide Inpatient Database

STUDY DESIGN

A retrospective cohort study with a national inpatient database.

OBJECTIVE

This study aimed to research the perioperative complication rates of cervical spondylotic myelopathy (CSM) patients who underwent anterior decompression with fusion (ADF) and posterior decompression with fusion (PDF) using a large national inpatient database and propensity score matching (PSM) analysis.

SUMMARY OF BACKGROUND DATA

There are several ways to successfully achieve surgical spinal decompression in CSM patients; however, evidence of the systemic complications and reoperation rates in ADF and PDF is lacking.

MATERIALS AND METHODS

We identified patients who were hospitalized for CSM and underwent either ADF or PDF from 2010 to 2016 using the Japanese Diagnosis Procedure Combination database. In the ADF and PDF groups, we compared postoperative complications (systemic and local), medical costs during hospitalization, and mortality before and after PSM. In addition, multivariate regression analysis was performed to identify risk factors for perioperative systemic complications.

RESULTS

A total of 1013 matched pairs were made after PSM. More perioperative systemic complications were detected in the ADF group than in the PDF group (at least 1 complication: ADF vs. PDF: 15.2% vs. 12.0%, P=0.038), especially for respiratory failure (1.4% vs. 0.4%, P=0.018), pneumonia (1.9% vs. 0.5%, P=0.004), and dysphagia (3.0% vs. 1.1%, P=0.003). The costs were ~$8000 higher (P<0.001) and the length of hospital stay was almost 5 days longer (P<0.001) in the PDF group. The risk factors for perioperative systemic complications in ADF were high age, low body mass index, and preoperative respiratory disease, and the factors in PDF were high body mass index and preoperative renal disease.

CONCLUSION

More systemic complications, especially respiratory events, were more frequently observed in the ADF group, while the medical costs were higher and the hospital stay was longer in the PDF group.

LEVEL OF EVIDENCE

Level III.

Establishment of a nomogram for predicting the surgical difficulty of anterior cervical spine surgery

Background

For a long time, surgical difficulty is mainly evaluated based on subjective perception rather than objective indexes. Moreover, the lack of systematic research regarding the evaluation of surgical difficulty potentially has a negative effect in this field. This study was aimed to evaluate the risk factors for the surgical difficulty of anterior cervical spine surgery (ACSS).

Methods

This was a retrospective cohort study totaling 291 consecutive patients underwent ACSS from 2012.3 to 2017.8. The surgical difficulty of ACSS was defined by operation time longer than 120 min or intraoperative blood loss equal to or greater than 200 ml. Evaluation of risk factors was performed by analyzing the patient’s medical records and radiological parameters such as age, sex, BMI, number of operation levels, high signal intensity of spinal cord on T2-weighted images, ossified posterior longitudinal ligament (OPLL), sagittal and coronal cervical circumference, cervical length, spinal canal occupational ratio, coagulation function index and platelet count.

Results

Significant differences were reported between low-difficulty and high-difficulty ACSS groups in terms of age (p = 0.017), sex (p = 0.006), number of operation levels (p < 0.001), high signal intensity (p < 0.001), OPLL (p < 0.001) and spinal canal occupational ratio (p < 0.001). Multivariate logistic regression analysis revealed that number of operation levels (OR = 5.224, 95%CI = 2.125–12.843, p < 0.001), high signal intensity of spinal cord (OR = 4.994, 95%CI = 1.636–15.245, p = 0.005), OPLL (OR = 6.358, 95%CI = 1.932–20.931, p = 0.002) and the spinal canal occupational ratio > 0.45 (OR = 3.988, 95%CI = 1.343–11.840, p = 0.013) were independently associated with surgical difficulty in ACSS. A nomogram was established and ROC curve gave a 0.906 C-index. There was a good calibration curve for difficulty estimation.

Conclusion

This study indicated that the operational level, OPLL, high signal intensity of spinal cord, and spinal canal occupational ratio were independently associated with surgical difficulty and a predictive nomogram can be established using the identified risk factors. Optimal performance was achieved for predicting surgical difficulty of ACSS based on preoperative factors.

Exclusion of Ossified Ligaments Behind C2 Vertebra Combined with Anterior Controllable Antedisplacement and Fusion for Cervical Ossification of the Posterior Longitudinal Ligament Extending to C2 Segment

OBJECTIVE

We sought to introduce an anterior surgical technique for cervical ossification of posterior longitudinal ligament (OPLL) extending to C2.

METHODS

A total of 29 patients with multilevel OPLL extending to C2 underwent surgery from January 2016 to January 2019. The rationale of our surgical technique is to transect the ossified ligament at the level of C2/3, dividing OPLL into 2 parts. OPLL behind the C2 vertebra is reserved as "focus exclusion," and OPLL below C2 is performed anterior controllable antedisplacement and fusion. Neurologic condition was evaluated using the Japanese Orthopaedic Association scoring system and its improvement ratio. Radiologic assessment included type and extent of OPLL, occupying rate, thickness and length of ossified mass, and curvature of spinal cord. Surgery- and implant-related complications were recorded.

RESULTS

The mean Japanese Orthopaedic Association score increased from 9.4 to 15.8 points at last follow-up, with a significant improvement (P < 0.01). The mean preoperative length of the ossified mass behind C2 was 15.4 mm, and its thickness was 2.2 mm, with no significant progression at last follow-up (15.3 mm and 2.2 mm, P > 0.05). There was also no statistical difference in OPLL thickness at the largest occupying rate level between preoperation and last follow-up (7.4 mm vs. 7.3 mm, P > 0.05). Four patients presented with cerebrospinal fluid leakage, 1 with screw displacement, and 1 with dysphagia.

CONCLUSIONS

For patients with cervical OPLL extending to C2, exclusion of ossified ligaments behind C2 combined with anterior controllable antedisplacement and fusion below C2 is an effective and alternative technique.

Risk factors related to perioperative systemic complications and mortality in elderly patients with osteoporotic vertebral fractures-analysis of a large national inpatient database

BACKGROUND

The surgical treatment of osteoporotic vertebral fractures (OVF) is generally associated with a high risk of complications due to an aging population with osteoporosis; however, the detailed risk factors for systemic complications and mortality have not been clarified. We evaluated the risk factors for systemic complications and mortality in surgically treated OVF patients using a large national inpatient database.

METHODS

Patients over 65 years old who were diagnosed with OVF and received either anterior fusion (AF) or posterior fusion (PF), from 2012 to 2016, were extracted from the diagnosis procedure combination (DPC) database. In each of the perioperative systemic complications (+) or (-) group, and the in-hospital death (+) or (-) group, we surveyed the various risk factors related to perioperative systemic complications and in-hospital death.

RESULTS

The significant factors associated with systemic complications were older age (OR 1.38, 95% CI 1.09-1.74), a lower activity of daily living score upon admission (OR 1.52, 95%CI 1.19-1.94), atrial fibrillation (OR 2.14, 95%CI 1.25-3.65), renal failure (OR 2.29, 95%CI 1.25-4.20), and surgical procedure (AF, OR 1.73, 95%CI 1.35-2.22). The significant explanatory variables for in-hospital death were revealed to be male sex (OR 3.26, 95%CI 1.20-8.87), a lower body mass index (OR 3.97, 95%CI 1.23-12.86), unscheduled admission (OR 3.52, 95%CI 1.17-10.63), atrial fibrillation (OR 8.31, 95%CI 2.25-30.70), renal failure (OR 7.15, 95%CI 1.32-38.77), and schizophrenia (OR 8.23, 95%CI 1.66-42.02).

CONCLUSIONS

Atrial fibrillation and renal failure as preoperative comorbidities were common factors between perioperative systemic complications and mortality in elderly patients for OVF.

Treatment of Thoracic Ossification of Posterior Longitudinal Ligament with One-Stage 360 Degree Circumferential Decompression Assisted by Piezosurgery

OBJECTIVES

To evaluate the safety and clinical efficacy of One-Stage 360 degree circular decompression for thoracic ossification of the posterior longitudinal ligament (TOPLL) assisted by piezosurgery.

MATERIALS AND METHODS

The present study enrolled 36 patients with TOPLL between August 2016 and February 2019. The average intraoperative bleeding volume of all 36 patients in this study is 1058.61 ±737.66 ml.

RESULTS

All patients did not experience any intraoperative complications such as spinal cord and nerve injuries, and 22 other complications related to decompression of OPLL cited in other literature; all of which were relieved after treatment. The resection time of single laminectomy was 3.43 ±0.49 min, and circular decompression was 42.06 ±14.22 min. At the last follow-up, the modified Japanese Orthopaedic Association (mJOA) score was 8.89 ±1.56, the recovery rate of spinal cord function was 64.2 ±21.2%, and the number of cases of spinal cord function deterioration was 0 (0%). The mJOA score of the last follow-up was negatively correlated with the time of circular decompression (r = 0.368, p ＜ 0.01) and age (r = 0.412, p = 0.026). The recovery rate of the spinal cord function was negatively correlated with the operation time of circular decompression (r = -0.325, p = 0.041) and the amount of intraoperative blood loss (r = -0.555, p = 0.028).

CONCLUSIONS

The use of piezosurgery can safely and effectively complete one-stage simple posterior TOPLL with 360-degree circular decompression. The incidence of complications is not high, and a good outcome can be obtained.

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

STUDY DESIGN

A retrospective comparative study.

OBJECTIVE

To compare the perioperative complications and costs of anterior decompression with fusion (ADF) and posterior decompression with fusion (PDF) for patients with cervical ossification of the posterior longitudinal ligament (OPLL).

SUMMARY OF BACKGROUND DATA

Surgical treatment of cervical OPLL has a high risk of various complications. ADF and PDF are effective for the treatment of cervical OPLL; however, few studies have compared the two procedures in terms of the perioperative surgical complications.

METHODS

Patients undergoing ADF and PDF for cervical OPLL from 2010 to 2016 were identified in a nation-wide inpatient database. We investigated systemic and local complications, length of hospital stay, costs for hospitalization, reoperation, and mortality. Propensity score was calculated from patients' characteristics and preoperative comorbidities, and one to one matching was performed.

RESULTS

Propensity score-matching produced 854 pairs of patients who underwent ADF and PDF. The rate of at least one systemic complication was significantly higher in the ADF group (P = 0.004). The incidence rates of postoperative respiratory failure (P = 0.034) and dysphagia (P = 0.008) were significantly higher in the ADF group. The rates of pneumonia (P = 0.06) and hoarseness (P = 0.08) also tended to be higher in the ADF group. However, no difference was found in the mortality rate (P = 0.22). In the local complications, spinal fluid leakage was significantly higher in the ADF group (P < 0.001). However, blood transfusion rate was significantly higher in the PDF group (P = 0.001). Hospital stay was significantly longer in the PDF group (P < 0.001) and the cost for hospitalization was greater in the PDF group (P < 0.001).

CONCLUSION

The present study demonstrated that perioperative complications, such as respiratory failure, dysphagia, and spinal fluid leakage, were more common in the ADF group. However, hospital stay was longer in the PDF group, and the cost for hospitalization was greater in the PDF group.

LEVEL OF EVIDENCE

3.

Ossification of the Posterior Longitudinal Ligament: Surgical Approaches and Associated Complications

Ossification of the posterior longitudinal ligament (OPLL) is a rare but potentially devastating cause of degenerative cervical myelopathy (DCM). Decompressive surgery is the standard of care for OPLL and can be achieved through anterior, posterior, or combined approaches to the cervical spine. Surgical correction of OPLL via any approach is associated with higher rates of complications and the presence of OPLL is considered a significant risk factor for perioperative complications in DCM surgeries. Potential complications include dural tear (DT) and subsequent cerebrospinal fluid leak, C5 palsy, hematoma, hardware failure, surgical site infections, and other neurological deficits. Anterior approaches are technically more demanding and associated with higher rates of DT but offer greater access to ventral OPLL pathology. Posterior approaches are associated with lower rates of complications but may allow for continued disease progression. Therefore, the decision to pursue either an anterior or posterior approach to surgical decompression may be critically influenced by complications associated with each procedure. The authors critically review anterior and posterior approaches to surgical decompression of OPLL with particular focus on the complications associated with each approach. We also review the recent work in developing new surgical treatments for OPLL that aim to reduce complication incidence.

The Clinical Implications and Complications of Anterior Versus Posterior Surgery for Multilevel Cervical Ossification of the Posterior Longitudinal Ligament; An Updated Systematic Review and Meta-Analysis

OBJECTIVE

Theoretically, the optimal approach is determined by the status of ossification of the posterior longitudinal ligament (OPLL) and sagittal alignment. However, there have long been disputes about the optimum surgical approach of OPLL. This study is to compare risk-effectiveness between anterior decompression and fusion (ADF) and laminoplasty and laminectomy with fusion (LP/LF) for the patient with cervical myelopathy due to multilevel cervical OPLL.

METHODS

We searched core databases, and compared complication and outcomes between ADF and LP/LF for patients with multiple OPLL for the cervical spine. The incidence of complications such as neurologic deterioration, C5 palsy, and dura tear was assessed. Changes in JOA score between baseline and final evaluations were assessed for 2 groups. The minimal clinically important difference (MCID) was utilized for evaluating clinical significance. We calculated Peto odds ratio (POR) and mean difference for the incidence and continuous variables, respectively.

RESULTS

We included data from 21 articles involving 3,872 patients with cervical myelopathy with OPLL. Major neurologic deficits such as paraplegia, quadriplegia developed 2.17% in the ADF group and 1.11% in the LP/LF group, and POR was 2.16. Mean difference of JOA score improvement of 2 groups was 1.30, and the mean difference showed a statistical significance. However, 1.3 points of JOA improvement cannot reach 2.5 points of the MCID.

CONCLUSION

Anterior surgery often led to rare but critical complications, and the difference of neurological improvement between 2 groups was below a clinically meaningful level. Posterior surgeries may be appropriate in the treatment of multilevel cervical myelopathy with OPLL.