Ex Vivo Porcine Models Are Valid for Testing and Training Microsurgical Lumbar Decompression Techniques.

BACKGROUND: Spinal surgeries are the leading causes for patient settlement issues. Recent European Medical Device Regulations aims to reduce complications by enforcing that surgical tools are validated before clinical use. Human cadavers are favored in preclinical use, but due to anatomic variance, decay, and scarce supply, alternative synthetic and animal models are used. This study evaluates the fidelity and validity of porcine models in training and assessment of microsurgical decompressive techniques in the lumbar spine. METHODS: Anatomic dimensions of 10 human and 5 young pig spines were assessed from computed tomography images. Novel "en bloc" fresh-frozen ex vivo porcine model tissues' fidelity and validity for decompressive surgery was evaluated by 3 expert neurosurgeons, in comparison with other models. RESULTS: The pigs' anatomic dimensions were on average 11% smaller than in humans. The pigs' L4-L5 was most alike humans, and the highest similarity was in lamina and spinous process widths, and the skin to posterior longitudinal ligament distance. Dimensional variability was higher in humans (F = 19.06-0.56, P < 0.05). The pigs' tissues were felt as good as living patients and better than cadavers for skin, fascia, bone, facets, ligamentum flavum, and dura, but poor for vessels (experts' intraclass correlation coefficient = 0.696-0.903). The pig models' validity for assessing drills' adverse features (friction, jitter, heating, and soft tissue trauma) was reported to be unanimously excellent. CONCLUSION: Pigs are representative for assessing microsurgical decompression techniques in the lower lumbar spine. The novel "en bloc" pig model can be an asset for industries and clinicians during assessment and training of new spinal techniques.

Tactile Skill-Based Neurosurgical Simulators Are Effective and Inexpensive.

BACKGROUND: Regulations limit residency work hours and operating time, limiting the amount of hands-on surgical training. To develop alternative hands-on training, many programs teach surgical skills in laboratories and workshops with the use of simulators. The expense of computer simulators and lack of replication of the manual skills and tactile feedback of surgery limit their usefulness. We have developed 2 replicable simulators constructed from low-cost materials, which allow residents to practice the manual skills required in key portions of minimally invasive lumbar decompression and Chiari decompression surgeries. The objective was to review the efficacy of our lumbar and Chiari decompression simulators in improving resident and medical student surgical skills. METHODS: Resident and medical student participants completed one or both simulators 10 times. The lumbar decompression simulations were evaluated by the length of time participants blocked the field of view and by the number of times they lost control of the drill. Chiari decompression simulations were evaluated by the length of time to complete the simulation and by the regularity of their sutures. RESULTS: After 10 attempts, participants of the lumbar decompression simulator decreased the amount of time blocking the field of view by 52% and decreased the number of times they lost control of the drill by 69%. Participants of the Chiari decompression simulator decreased their suturing time by 56% and improved the regularity of their sutures. CONCLUSIONS: The simple and inexpensive simulators evaluated in this study were shown to improve the speed, quality of work, and comfort level of the participants.

Learning curve and clinical outcomes of percutaneous endoscopic transforaminal decompression for lumbar spinal stenosis.

PURPOSE: To define and analyze the learning curve of percutaneous endoscopic transforaminal decompression (PETD) for lumbar spinal stenosis (LSS). METHODS: From July 2015 to September 2016, 78 patients underwent PETD; one of whom was converted to open surgery, two were lost, and 75 were included in this study. Clinical results were assessed by using the Oswestry Disability Index (ODI) and visual analog scale (VAS). The learning curve was assessed by a logarithmic curve-fitting regression analysis. Of these 75 patients, 35 were defined as the "early" group, and 40 were defined as the "late" group for comparison. RESULTS: The mean follow-up was 25.37 ± 4.71 months. The median operative time gradually decreased from 95 (interquartile range, IQR, 85-110) minutes for the early group to 70 (IQR, 60-80) minutes for the late group (P < .000), and an asymptote was reached after approximately 35 cases. After surgery, the VAS for leg pain (LP) and ODI decreased significantly and remained constant during the follow-up. However, the VAS of low back pain (LBP) increased mildly. The total complication rate was 6.6%. ODI, VAS of LP and of LBP, and complication rate did not significantly differ between two groups. Early ambulation and short hospital stay after surgery were achieved. CONCLUSION: The learning curve of PETD for LSS was assessed and good clinical results were achieved. The surgeon's experience with this technique correlated with reduced operation time. Proper patient selection, familiarity with pathological anatomy, and manipulation under endoscopic view may shorten the learning curve and decrease complications.

Surgical training in spine surgery: safety and patient-rated outcome.

PURPOSE: The aim of this study was to investigate the difference in patient-reported outcomes and surgical complication rates between lumbar procedures carried out either by experienced board-certified spine surgeons (BCS) or by supervised spine surgery residents (RES) in a large Swiss teaching hospital. METHODS: This was a single-center retrospective analysis of data collected prospectively within the framework of the EUROSPINE Spine Tango Registry. It involved the data of 1415 patients undergoing first-time surgery in our institution between the years 2004 and 2016. Patients were divided into three groups based on the surgical procedure: lumbar single-level fusion (SLF), single-level decompression (SLD) for lumbar spinal stenosis and disc hernia procedures (DH). Patient-reported outcome measures (primary outcome) included the multidimensional Core Outcome Measures Index (COMI) preoperatively and 3 and 12 months postoperatively plus single items concerning satisfaction with care and global treatment outcome (GTO). Secondary outcomes included surgical variables such as blood loss, duration of surgery, complication rates and length of stay. RESULTS: There were no significant differences between the RES and BCS patient groups for most of the demographic and baseline clinical variables with the exception of age in the SLD group (p = 0.012), BMI in the DH group (p = 0.02) and leg pain in the SLF group (p = 0.03). COMI scores improved significantly after all three types of procedure (p < 0.0001) without significant difference (p > 0.05) between the patients of RES and BCS. There was no significant difference (p > 0.05) between RES and BCS patients with regard to satisfaction and GTO. There were no significant differences between RES and BCS (p > 0.05) in the surgical or medical complication rates. CONCLUSION: In the given setting, surgical training of spine surgery residents under guided supervision by board-certified spine surgeons was shown to be safe, as it was not associated with greater morbidity or mortality. Furthermore, it had no detrimental influence on patient-reported outcomes. The findings can be used to give reassurance to prospective patients that are to be operated on by supervised spine surgery residents. These slides can be retrieved under Electronic Supplementary Material.

Learning Curve for Lumbar Decompressive Laminectomy in Biportal Endoscopic Spinal Surgery Using the Cumulative Summation Test for Learning Curve.

OBJECTIVE: The purpose of the present study was to determine the learning curve for biportal endoscopic spinal surgery (BESS) for decompressive laminectomy in lumbar spinal stenosis using a learning curve cumulative summation test (LC-CUSUM). METHODS: The surgeon was proficient in open and microscopic decompressive laminectomy in lumbar spinal stenosis but did not have any experience with BESS or other endoscopic surgery techniques. The learning curve of BESS was investigated using LC-CUSUM analysis. Procedure success was defined as an operative time <75 minutes, the mean operative time with microscopic decompression laminectomy. RESULTS: The present study included the first 60 patients who had undergone single-level decompressive laminectomy using BESS by a single orthopedic surgeon. The mean operative time for decompressive laminectomy by BESS was 83.8 ± 37.9 minutes. The mean operative time in the early learning period (≤30 cases) and late learning period (second 30 cases) was 105.3 ± 39.7 minutes and 62.4 ± 19.9 minutes, respectively. The overall complication rate was ∼10%. The LC-CUSUM signaled competency for surgery at the 58th operation, indicating that sufficient evidence had accumulated to prove that the surgeon was competent. Thus, a trainee with no experience with BESS had reached adequate performance at 58 cases. CONCLUSIONS: The results of the present study have demonstrated that a substantial learning period could be needed before adequate performance can be achieved with lumbar decompressive laminectomy using BESS.

Three-dimensionally printed vertebrae with different bone densities for surgical training.

PURPOSE: To evaluate whether 3D-printed vertebrae offer realistic haptic simulation of posterior pedicle screw placement and decompression surgery with normal to osteoporotic-like properties. METHODS: A parameterizable vertebra model was developed, adjustable in cortical and cancellous bone thicknesses. Based on this model, five different L3 vertebra types (α, ß, γ1, γ2, and γ3) were designed and fourfold 3D-printed. Four spine surgeons assessed each vertebra type and a purchasable L3 Sawbones vertebra. Haptic behavior of six common steps in posterior spine surgery was rated from 1 to 10: 1-2: too soft, 3-4: osteoporotic, 5-6: normal, 7-8: hard, and 9-10: too hard. Torques were measured during pedicle screw insertion. RESULTS: In total, 24 vertebrae (six vertebra types times four examiners) were evaluated. Mean surgical assessment scores were: α 3.2 ± 0.9 (osteoporotic), ß 1.9 ± 0.7 (too soft), γ1 4.7 ± 0.9 (osteoporotic-normal), γ2 6.3 ± 1.1 (normal), and γ3 7.5 ± 1.1 (hard). All surgeons considered the 3D-printed vertebrae α, γ1, and γ2 as more realistic than Sawbones vertebrae, which were rated with a mean score of 4.1 ± 1.7 (osteoporotic-normal). Mean pedicle screw insertion torques (Ncm) were: α 32 ± 4, ß 12 ± 3, γ1 74 ± 4, γ2 129 ± 13, γ3 196 ± 34 and Sawbones 90 ± 11. CONCLUSIONS: In this pilot study, 3D-printed vertebrae displayed haptically and biomechanically realistic simulation of posterior spinal procedures and outperformed Sawbones. This approach enables surgical training on bone density-specific vertebrae and provides an outlook toward future preoperative simulation on patient-specific spine replicas. These slides can be retrieved under Electronic Supplementary Material.

Minimally invasive lumbar decompression-the surgical learning curve.

BACKGROUND CONTEXT: Minimally invasive spine surgery (MIS) procedures carry an inherently difficult learning curve based upon anecdotal evidence. Few studies have investigated the surgeon's learning curve for MIS lumbar laminectomy or laminotomy with or without discectomy. PURPOSE: To characterize the learning curve of a 1- or 2-level MIS lumbar decompression (LD) based on perioperative and postoperative parameters . STUDY DESIGN/SETTING: Retrospective analysis of a prospectively maintained registry was used for this study. PATIENT SAMPLE: There were 228 consecutive patients who underwent a primary 1- or 2-level MIS LD by a single surgeon for degenerative spinal pathology from 2009 to 2014. From 2005 to 2006, 50 patients underwent 1- or 2-level open LD consecutively. OUTCOME MEASURES: Perioperative and postoperative outcomes (complications, visual analogue scale [VAS] scores, reoperations) were the outcome measures for this study. METHODS: Patients were stratified into first and second groups as determined by the case number at which the procedural time reached a plateau. Demographics, comorbidity, pain scores, and surgical outcomes were compared between the first 50 patients and the subsequent 178 patients. The secondary analysis compared the surgical outcomes between the initial 50 MIS and 50 open LD patients. No funds were received in support of this work. RESULTS: The initial cohort was older with a higher comorbidity burden (p<.05). However, body mass index, gender, smoking status, and ethnicity did not differ between cohorts. The initial cohort incurred a greater procedural time (p<.001) and longer length of hospitalization (p<.05) than the second cohort. Estimated blood loss (EBL), pain scores, complication rates, recurrent herniation rates, and reoperation rates were similar between groups. In the secondary analysis, the open LD patients demonstrated greater procedural time, higher EBL, and longer length of hospital stay than the MIS patients. However, the reoperation rate and 30-day readmission rate were not different between the MIS and open patients. CONCLUSIONS: Continued surgical experience was associated with a reduced operative time, shorter length of hospitalization, and similar blood loss following an MIS LD. Independent of surgical experience, all patients demonstrated similar improvements in clinical outcomes. These findings appear to suggest that although surgical experience may improve perioperative parameters (operative time, length of hospitalization), an MIS LD may initially be performed safely without prior experience.

Microscopic lumbar spinal stenosis decompression: is surgical education safe?

BACKGROUND: Acquiring operative skills in the course of a structured neurosurgery residency training program is vital to safely operating on patients autonomously upon board certification. We tested the hypothesis that the complication rates and outcome of microscopic lumbar spinal stenosis (LSS) decompression done by supervised residents are not inferior to those of board-certified faculty neurosurgeons (BCFNs). METHODS: Retrospective single-center study performed at a Swiss teaching hospital comparing consecutive patients undergoing surgery for LSS by a supervised neurosurgery resident (teaching cases) to a consecutive series of patients operated on by a BCFN (non-teaching cases). The primary endpoint was occurrence of complications during surgery. Secondary endpoints were patients' clinical outcomes 4 weeks after surgery, categorized into a binary responder and non-responder variable, occurrence of postoperative complications, need for re-do surgery, and clinical outcome until the last follow-up (FU). RESULTS: In a total of n = 471 operations, n = 194 (41.2 %) were teaching cases and n = 277 (58.8 %) non-teaching cases. A longer operation time (single-level procedures: mean 100.0 vs. 83.2 min, p < 0.001) was recorded for teaching cases, while estimated blood loss was equal (single-level procedures: mean 109.9 vs. 117.0 ml, p = 0.409). In multivariate analysis, supervised residents were as likely as BCFNs to have an intraoperative complication (OR 0.92, 95 % CI 0.41-2.04, p = 0.835). They were as likely as BCFNs to achieve a favorable 4-week response to surgery (OR 1.82, 95 % CI 0.79-4.15, p = 0.155). Until final FU, the likelihood for patients in the teaching group to suffer from postoperative complications (OR 1.07, 95 % CI 0.46-2.49, p = 0.864) or require re-do surgery (OR 0.68, 95 % CI 0.31-1.52, p = 0.358) was similar to that of the non-teaching group. CONCLUSIONS: Complication rates and short- and mid-term outcomes following LSS decompression were comparable for patients operated on by supervised neurosurgery residents and senior neurosurgeons. Our data thus indicate that a structured neurosurgical hands-on training including LSS decompression is safe for patients.

Using augmented reality as a clinical support tool to assist combat medics in the treatment of tension pneumothoraces.

This study was to extrapolate potential roles of augmented reality goggles as a clinical support tool assisting in the reduction of preventable causes of death on the battlefield. Our pilot study was designed to improve medic performance in accurately placing a large bore catheter to release tension pneumothorax (prehospital setting) while using augmented reality goggles. Thirty-four preclinical medical students recruited from Morehouse School of Medicine performed needle decompressions on human cadaver models after hearing a brief training lecture on tension pneumothorax management. Clinical vignettes identifying cadavers as having life-threatening tension pneumothoraces as a consequence of improvised explosive device attacks were used. Study group (n = 13) performed needle decompression using augmented reality goggles whereas the control group (n = 21) relied solely on memory from the lecture. The two groups were compared according to their ability to accurately complete the steps required to decompress a tension pneumothorax. The medical students using augmented reality goggle support were able to treat the tension pneumothorax on the human cadaver models more accurately than the students relying on their memory (p < 0.008). Although the augmented reality group required more time to complete the needle decompression intervention (p = 0.0684), this did not reach statistical significance.

The development of an evidence-based patient booklet for patients undergoing lumbar discectomy and un-instrumented decompression.

Post-operative management after lumbar surgery is inconsistent leading to uncertainty amongst surgeons and patients about post-operative restrictions, reactivation, and return to work. This study aimed to review the evidence on post-operative management, with a view to developing evidence-based messages for a patient booklet on post-operative management after lumbar discectomy or un-instrumented decompression. A systematic literature search produced a best-evidence synthesis of information and advice on post-operative restrictions, activation, rehabilitation, and expectations about outcomes. Evidence statements were extracted and developed into patient-centred messages for an educational booklet. The draft text was evaluated by peer and patient review. The literature review found little evidence for post-operative activity restrictions, and a strong case for an early active approach to post-operative management. The booklet was built around key messages derived from the literature review and aimed to reduce uncertainty, promote positive beliefs, encourage early reactivation, and provide practical advice on self-management. Feedback from the evaluations were favourable from both review groups, suggesting that this evidence-based approach to management is acceptable and it has clinical potential.