The influence of COVID-19 epidemic on the number of orthopaedic surgeries in Japan.

BACKGROUND: There is limited data on the impact of COVID-19 epidemic on the number of orthopaedic surgeries in Japan. METHODS: We conducted a nationwide hospital survey asking for the monthly number of orthopaedic surgeries performed at each facility from January 2019 to June 2021. Those facilities that had performed at least 100 surgeries in 2019 were included for analyses. The facilities were further grouped by prefecture and by hospital characteristics. A brief health economic evaluation was also performed. Risk ratios were compared using univariate analyses with P < 0.05 considered statistically significant. RESULTS: Questionnaire was sent to 1988 hospitals with 1671 hospitals (84%) responding. The survey data indicated a total number of orthopaedic surgeries decreased in 2020 compared to 2019 (1,061,541 vs 1,119,955 P < 0.01), and also for the first six months of 2021 compared to the same period in 2019 (530,388 vs 550,378 P < 0.01). In 2020, over 50% of all facilities in nearly all of the prefectures saw a decline in surgical procedures. The risk of incurring more than a 25% decease in the number of surgeries was significantly higher in 2020 for class I designated medical institutions compared to those that were not designated for any types of infectious diseases among the institutions with a tertiary emergency medical center in 2020 (crude risk ratio 2.9: 95% CI 1.2-7.4, p = 0.02) and in 2021 (crude risk ratio 4.7: 95% CI 1 0.9-12.1, p < 0.01). The estimated total nationwide decrease of revenue were in the range of approximately ¥29.2 to ¥116.8 billion per year for orthopaedic surgeries alone. CONCLUSION: There was a statistically significant decrease in the number of orthopaedic surgeries in Japan. The magnitude of the decline varied by prefectures and hospital characteristics, with the greater impact imposed on medical institutions with higher classification functions. The estimated immediate health economic impact was sizable.

Operating Costs of Full-endoscopic Lumbar Spine Surgery in Japan.

For full-endoscopic lumbar discectomy, operating costs are also important because expensive equipment are necessary. We surveyed the operating costs of surgical equipment necessary for full-endoscopic surgery together with surgical procedure reimbursement fees. A total of 295 cases of full-endoscopic surgery via a transforaminal approach were retrospectively analyzed. We calculated the frequency of damage and the unit purchase price of devices such as endoscopes, and surgical instruments such as grasping forceps for nucleotomy, high-speed drill bar, and bipolar forceps, and examined the operating costs in Japanese yen against the procedure fee per case. Endoscope breakage occurred seven times, and a payment of ¥760,000 was necessary for trade-in and purchase of a new endoscope. The total breakage number of grasping forceps was 58, and the purchase price per unit was ¥116,000. Therefore, a total of ¥12,020,000 was required for the 295 cases, and the calculated operating cost that accompanies equipment breakage was ¥40,000 per case. In addition, about ¥118,000 was required for disposable bipolar forceps and high-speed drill bar to be used intraoperatively for each case. Thus, for one case it is calculated that total ¥158,000 is utilized for equipment from the surgical reimbursement fee per case specified by the Japanese Ministry of Health being ¥303,900. Minimally invasive procedures provide great benefit to patients; however, the eventual contribution to hospital profits is small and may not be sufficient. To resolve this issue, the cost of surgical equipment should be lowered and/or the surgical reimbursement fee of the full-endoscopic surgery should be raised.

Diffusion tensor imaging and tractography of the sciatic nerve: assessment of fractional anisotropy and apparent diffusion coefficient values relative to the piriformis muscle, a preliminary study.

OBJECTIVE: Piriformis muscle syndrome (PMS) is underdiagnosed. To evaluate the potential of diffusion tensor imaging and diffusion tensor tractography as innovative tools for the diagnosis of PMS by functional assessment of the sciatic nerve, the aims of this study are to assess the reproducibility and to evaluate the changes in the parameters at levels proximal and distal to the piriformis. MATERIALS AND METHODS: Fractional anisotropy (FA) and the apparent diffusion coefficient (ADC) of the sciatic nerve at three levels were quantified twice each by two examiners using the fiber-tracking method. In the first part of the study, laterality and reproducibility were evaluated using intraclass correlation coefficients (ICC) in ten healthy volunteers. In the second part of the study, the healthy side and symptomatic side were assessed in ten consecutive patients with sciatica. There were three patients with no findings on lumbar magnetic resonance imaging (MRI). RESULTS: There was no laterality in either FA or ADC values in asymptomatic patients at any level. The mean intra-rater ICC was 0.90 and the mean inter-rater ICC was 0.87. FA was significantly lower and ADC significantly higher on the symptomatic side at each level in patients with sciatica. In the three sciatica patients with no findings on lumbar MRI, FA was significantly lower and ADC was significantly higher only at levels distal to the piriformis. These patients experienced full pain relief after ultrasound-guided injection of local anesthesia. CONCLUSIONS: Diffusion tensor imaging and diffusion tensor tractography might be innovative tools for the diagnosis of PMS.

Risk Assessment of Lumbar Segmental Artery Injury During Lateral Transpsoas Approach in the Patients With Lumbar Scoliosis.

STUDY DESIGN: A retrospective study using 27 contrast-enhanced multi-planar computed tomography scans of subjects with lumbar scoliosis. OBJECTIVE: To assess the risk of injury of lumbar segmental arteries during transpsoas approach in patients with lumbar scoliosis. SUMMARY OF BACKGROUND DATA: Although lumbar interbody fusion using big intervertebral cage through transpsoas approach has a big advantage to correct coronal and sagittal deformity in patients with spinal deformity, the risk for injury of lumbar segmental artery is always concerned. METHODS: The abdominal-contrast enhanced multi-planar computed tomography scans of 27 subjects with lumbar scoliosis with over 15° of Cobb angle were retrospectively reviewed. The coronal views through the posterior one third of the intervertebral discs were reviewed. The cranio-caudal intervals of the adjacent segmental arteries at each intervertebral level were measured. The recommended working space for the lateral transpsoas approach using extreme lateral interbody fusion retractor is 24 mm in the cranio-caudal direction. The cutoff value for an intersegmental Cobb angle that would estimate a cranio-caudal interval of less than 24 mm was determined using a receiver operating characteristic curve. RESULTS: The average interval between the cranio-caudal lumbar segmental arteries on the concave side was significantly shorter than that on the convex side (29.9 vs. 33.6 mm, P < 0.05). The differences in the intervals between the convex and concave sides were correlated with the corresponding intersegmental Cobb angle (r = 0.65, P < 0.05). Receiver operating characteristic curve analysis revealed that cutoff value for the best prediction of an interval less than 24 mm was 14.5°, with a specificity of 94.3% and sensitivity of 71.4%. CONCLUSION: This study demonstrated that female patients with lumbar scoliosis with an intersegmental Cobb angle higher than 14.5° would be at high risk for potential injury to the lumbar artery during a transpsoas approach for extreme lateral interbody fusion from the concave side. LEVEL OF EVIDENCE: 4.

Risk Management for Avoidance of Major Vascular Injury due to Lateral Transpsoas Approach.

STUDY DESIGN: A retrospective study using 323 contrast-enhanced, multi-planner three-dimensional computed (3D-CT) scans. OBJECTIVE: The aim of this study was to identify risk factors for injury to the major vessels in the lateral transpsoas approach. SUMMARY OF BACKGROUND DATA: To avoid critical complications such as major vessel injury, it is essential to examine anatomical information related to preoperative risk management that is specific to the lateral transpsoas approach. METHODS: The abdominal contrast-enhanced, multi-planner 3D-CT scans of 323 consecutive subjects (203 males and 120 females, 15-89 years old) were retrospectively reviewed. The true axial views were used for evaluation of the locations of the major vein and artery at L3 to L4 and L4 to L5. According to the Moro system, the axial view was divided into 6 zones from the front side (A, I II, III, IV, P) and the locations of the dorsal tangential line of the major vessels were evaluated. RESULTS: At the L3 to L4 level, the dorsal tangential line of the major vein located in zone A was found in 18% of subjects, in zone I in 74%, and in zone II in 8%. The line of the major artery was located in zone A in 92.6% of subjects and in zone I in 7.1%. At the L4 to L5 level, the line of the major vein was located in zone A in 5% of subjects, in zone I in 75%, in zone II in 20%, and in zone III in only 1 subject. The line of the major artery was identified in zone A in 87% of subjects, in zone I in 12%, and in zone II in 1%. Women had significant dorsal-migrated veins and arteries at both spinal levels (P < 0.01). CONCLUSION: To avoid critical complications in extreme lateral lumbar interbody fusion, careful preoperative radiological evaluation of the major vessels and intraoperative care are important. LEVEL OF EVIDENCE: 3.

Consecutive assessment of FA and ADC values of normal lumbar nerve roots from the junction of the dura mater.

BACKGROUND: Diffusion weighted imaging (DWI) and diffusion tensor imaging (DTI) are widely used in the evaluation of the central nervous system and recently have been reported as a potential tool for diagnosis of the peripheral nerve or the lumbar nerve entrapment. The purpose of this study was to evaluate consecutive changes in apparent diffusion coefficient (ADC) and fractional anisotropy (FA) values of normal lumbar nerve roots from the junction of the dura mater. METHODS: The lumbar spinal nerves were examined in 6 male healthy volunteers (mean age, 35 years) with no experiences of sciatica, with a 3.0-T MR unit using a five-element phased-array surface coil. DTI was performed with the following imaging parameters: 11084.6/73.7 ms for TR/TE; b-value, 800 s/mm2; MPG, 33 directions; slice thickness, 1.5 mm; and total scan time, 7 min 35 s. ADC and FA values at all consecutive points along the L4, L5 and S1 nerves were quantified on every 1.5 mm slice from the junction of the dura mater using short fiber tracking. RESULTS: ADC values of all L4, 5, and S1 nerve roots decreased linearly up to 15 mm from the dura junction and was constant distally afterward. ADC values in the proximal portion demonstrated S1 > L5 > L4 (p < 0.05). On the other hand, FA values increased linearly up to 15 mm from the dura junction, and was constant distally afterward. FA values in the proximal portion showed L4 > L5 > S1 (p < 0.05). CONCLUSION: Our study demonstrated that ADC and FA values of each L4, 5, and S1 at the proximal portion from the junction of the dura matter changed linearly. It would be useful to know the normal profile of DTI values by location of each nerve root so that we can detect subtle abnormalities in each nerve root.