Learning Curve for Interlaminar Endoscopic Lumbar Discectomy: A Systematic Review.

BACKGROUND: Interlaminar endoscopic lumbar discectomy (IELD) is an efficient surgical treatment for lumbar disc herniation. However, this minimally invasive procedure requires a considerable learning curve that has not yet been standardized. This review aimed to evaluate the learning curve's characteristics, including the cutoff point required to achieve technical proficiency and to discuss appropriate training methods. METHODS: We systematically searched the core databases (PubMed, Embase, and Cochrane Library) for clinical studies that evaluated the learning curve using quantitative data. We performed a quality assessment using the Newcastle-Ottawa scale. We also compared descriptive statistics, including operative time and other variables before and after the cutoff point. RESULTS: Six studies reporting 302 cases of IELD were selected from 7188 screened articles. The cutoff point was randomly set in 3 studies and determined as the curve's asymptote in 3 studies. The mean value for the cutoff point was 22.17 ± 12.40 cases (range: 10-43 cases) and mainly determined based on the operative time, which was shorter in the late group than that in the early group (P < 0.05). The cutoff points were not significant for patient outcome parameters such as pain score, functional result, surgical failure, or complications. CONCLUSIONS: The evidence of published studies regarding the learning curve for the IELD technique is insufficient. The reported cutoff points may be significant only for task efficiency. Moreover, they may not represent the asymptote of the curve. Future studies should evaluate the actual plateau points using patient outcome data.

Impact of medical student involvement on outcomes following spine surgery: A single center analysis of 6485 patients.

Medical student (MS) observation and assistance in the operating room (OR) is a critical component of medical education. Though participation in the operating room has many benefits to the medical student, the potential cost of these experiences to the patients must be taken into account. Other studies have shown differences in outcomes with resident involvement, but the effect of medical students in the OR has been poorly understood. The objective of this study was to understand how medical students and residents impacted surgical outcomes in posterior spinal fusions, anterior cervical discectomy and fusions (ACDFs), and lumbar discectomies. We conducted a retrospective study of patients undergoing posterior spinal fusions, ACDFs, and lumbar discectomies over 15 years. There were 6485 patients met the inclusion criteria of either undergoing a posterior fusion, ACDF or lumbar discectomy (1250 posterior fusion, 1381 ACDF, 3854 lumbar discectomies). Overall, little difference was observed when a medical student was present for surgical outcomes including length of stay, infection, and readmission. For ACDFs, having a medical student present had a significantly longer procedure durations (OR = 1.612, p = 0.001) than cases without. Besides slightly longer operative time (in posterior fusions), there were no major differences in outcomes when a medical student was present in the OR.

Surgical skills: Can learning curves be computed from recordings of surgical activities?

PURPOSE: Surgery is one of the riskiest and most important medical acts that are performed today. The need to improve patient outcomes and surgeon training, and to reduce the costs of surgery, has motivated the equipment of operating rooms with sensors that record surgical interventions. The richness and complexity of the data that are collected call for new methods to support computer-assisted surgery. The aim of this paper is to support the monitoring of junior surgeons learning their surgical skill sets. METHODS: Our method is fully automatic and takes as input a series of surgical interventions each represented by a low-level recording of all activities performed by the surgeon during the intervention (e.g., cut the skin with a scalpel). Our method produces a curve describing the process of standardization of the behavior of junior surgeons. Given the fact that junior surgeons receive constant feedback from senior surgeons during surgery, these curves can be directly interpreted as learning curves. RESULTS: Our method is assessed using the behavior of a junior surgeon in anterior cervical discectomy and fusion surgery over his first three years after residency. They revealed the ability of the method to accurately represent the surgical skill evolution. We also showed that the learning curves can be computed by phases allowing a finer evaluation of the skill progression. CONCLUSION: Preliminary results suggest that our approach constitutes a useful addition to surgical training monitoring.

Introducing Interlaminar Full-Endoscopic Lumbar Diskectomy: A Critical Analysis of Complications, Recurrence Rates, and Outcome in View of Two Spinal Surgeons' Learning Curves.

Background and Study Objective Interlaminar full-endoscopic diskectomy is a minimally invasive surgical alternative to microdiskectomy for the treatment of lumbar disk herniation. The authors analyze their surgical results and learning curves during and after the introductory phase of this surgical technique. Patients and Methods We present a case review of 76 patients operated on using interlaminar full-endoscopic diskectomy. We retrospectively analyzed two spinal surgeons' learning curves in terms of operation time with respect to intraoperative blood loss, conversion rates, complications, infections, length of hospitalization, need for rehabilitation, recurrence rates, pain intensity, and opioid use. Patients' functional status and Health-related Quality of Life were assessed by follow-up questionnaires for 47 patients, using the North American Spine Society Score and the Short Form 12 in addition to long-term pain intensity, work capacity, and patient satisfaction with the operation. Results A steady state of the learning curve (operation time) of an experienced spinal surgeon was reached after 40 cases. Supervision by a more experienced surgeon can shorten the learning curve. The rate of conversions (10%), complications (5%), and recurrent lumbar disk herniations (28%) did not negatively affect the long-term outcome in patients operated on before and after the learning phase. Patient satisfaction was high. Conclusions The rate of conversions, complications, and recurrent lumbar disk herniations compared with microdiskectomy combined with the challenging learning curve should be considered before surgeons adopt this procedure. Supervision by an endoscopically experienced spinal surgeon during the introductory phase is highly advisable.

Anterior Cervical Discectomy and Fusion: The Surgical Learning Curve.

STUDY DESIGN: Case-series OBJECTIVE.: The aim of the study was to investigate changes in intraoperative and postoperative parameters associated with the surgical learning curve for anterior cervical discectomy and fusion (ACDF). SUMMARY OF BACKGROUND DATA: ACDF is a common surgical spine procedure. The surgical learning curve for this procedure has not been previously characterized. METHODS: A prospectively maintained surgical database of consecutive patients who underwent primary 1-2 level ACDF for degenerative spine disease from 2006 to 2014 was reviewed. Patients with concurrent or revision procedures were excluded. The series began after the surgeon's fellowship and includes his first case as an attending. A total of 374 patients were divided sequentially into cohorts of 125 (early), 125 (middle), and 124 (late). Statistical analyses utilized independent sample t tests, chi squared tests, and multivariate regression adjusted for preoperative characteristics. The learning curve of operative time was characterized using three-parameter asymptotic regression and two separate linear regressions. RESULTS: The earliest cohort had a greater comorbidity burden, percentage of smokers, and Medicare patients, with fewer workers' compensation patients when compared to later cohorts. Later cohorts demonstrated decreased mean operative time and estimated blood loss (EBL) and increased arthrodesis rate. Asymptotic and linear regression analyses demonstrated that 50% of the learning curve occurred at case 17 and 31, respectively, whereas 90% of potential improvement occurred by case 56 and 57, respectively. CONCLUSION: A significant learning curve exists for surgeons performing ACDFs. Patients undergoing ACDF will experience shorter operations, less EBL, and greater arthrodesis rates as the surgeon gains experience. Operative proficiency can be expected to occur by case 60, with arthrodesis rate increasing over a longer period. These results suggest that despite longer operative times and increased EBL with earlier cases, ACDF can safely and effectively be performed at the onset of a surgeon's career. This conclusion may be useful to new surgeons debating between operative and nonoperative management of cervical degenerative disc disease. LEVEL OF EVIDENCE: 4.

[THE ALTERNATIVE MODEL IN TRAINING FOR OPERATION MANAGEMENT ON LUMBAR SPINE].

The authors proposed to use a lumbar part of calf carcass as a new biological model for training of basic practical skills in order to perform the neurosurgical operative interventions on the spine. The proximity of anatomico-surgical parameters of given model and human cavader lumbar spine was estimated. The study proved the possibility of use of lumbar part of calf carcass for training techniques of transpedicular fixation and microdiskectomy in lumbar part.

Anterior cervical discectomy and fusion: is surgical education safe?

BACKGROUND: Operative skills are key to neurosurgical resident training. They should be acquired in a structured manner and preferably starting early in residency. The aim of this study was to test the hypothesis that the outcome and complication rate of anterior cervical discectomy and fusion with or without instrumentation (ACDF(I)) is not inferior for supervised residents as compared to board-certified faculty neurosurgeons (BCFN). METHODS: This was a retrospective single-center study of all consecutive patients undergoing ACDF(I)-surgery between January 2011 and August 2014. All procedures were dichotomized into two groups according to the surgeon's level of experience: teaching cases (postgraduate year (PGY)-2 to PGY-6 neurosurgical residents) and non-teaching cases operated by BCFN. The primary study endpoint was patients' clinical outcome 4 weeks after surgery, categorized into a binary responder and non-responder variable. Secondary endpoints were complications, need for re-do surgery, and clinical outcome until the last follow-up. RESULTS: After exclusion of six cases because of incomplete data, a total of 287 ACDF(I) operations were enrolled into the study, of which 82 (29.2 %) were teaching cases and 199 (70.8 %) were non-teaching cases. Teaching cases required a longer operation time (131 min (95 % confidence interval (CI) 122-141 min) vs. 102 min (95-108 min; p < 0.0001) and were associated with a slightly higher estimated blood loss (84 ml (95 % CI 56-111 ml) vs. 57 ml (95 % CI 47-66 ml); p = 0.0017), while there was no difference in the rate of intraoperative complications (2.4 vs. 1.5 %; p = 0.631). Four weeks after surgery, 92.7 and 93 % of the patients had a positive response to surgery (p = 1.000), respectively. There was no difference in the postoperative complication rate (4.9 vs. 3.0 %; p = 0.307). Around 30 % of the study patients were followed up in outpatient clinics for more than once up until a mean period of 6.4 months (95 % CI 5.3-7.6 months). At the last follow-up, the clinical outcome was similar with a 90 % responder rate for both groups (p = 0.834). In total, five patients from the teaching group and eight patients from the non-teaching group required re-do surgery (p = 0.602). CONCLUSIONS: Short- and mid-term outcomes and complication rates following microscopic ACDF(I) were comparable for patients operated on by supervised neurosurgical residents or by senior surgeons. Our data thus indicate that a structured neurosurgical education of operative skills does not lead to worse outcomes or increase the complication rates after ACDF(I). Confirmation of the results by a prospective study is desired.

Development and validation of an artificial wetlab training system for the lumbar discectomy.

PURPOSE: An initial research indicated that realistic haptic simulators with an adapted training concept are needed to enhance the training for spinal surgery. METHODS: A cognitive task analysis (CTA) was performed to define a realistic and helpful scenario-based simulation. Based on the results a simulator for lumbar discectomy was developed. Additionally, a realistic training operating room was built for a pilot. The results were validated. RESULTS: The CTA showed a need for realistic scenario-based training in spine surgery. The developed simulator consists of synthetic bone structures, synthetic soft tissue and an advanced bleeding system. Due to the close interdisciplinary cooperation of surgeons between engineers and psychologists, the iterative multicentre validation showed that the simulator is visually and haptically realistic. The simulator offers integrated sensors for the evaluation of the traction being used and the compression during surgery. The participating surgeons in the pilot workshop rated the simulator and the training concept as very useful for the improvement of their surgical skills. CONCLUSIONS: In the context of the present work a precise definition for the simulator and training concept was developed. The additional implementation of sensors allows the objective evaluation of the surgical training by the trainer. Compared to other training simulators and concepts, the high degree of objectivity strengthens the acceptance of the feedback. The measured data of the nerve root tension and the compression of the dura can be used for intraoperative control and a detailed postoperative evaluation.

Early surgical education of residents is safe for microscopic lumbar disc surgery.

INTRODUCTION: It is a well-established dogma that many surgeons do not reach a quintessential level of their technical operative skills until successful completion of their training program. The aim of this study was to test the hypothesis that early introduction of supervised residents to non-complex spinal surgical procedures within a structured and supervised educational program does not harm the patient in terms of higher complication rates or worse pain- and health-related quality of life (HrQOL) outcomes. METHODS: A prospective study on 102 patients undergoing surgery for lumbar disc herniation (LDH) was performed. The procedures were dichotomized into two groups according to the surgeon's level of experience: teaching cases (neurosurgical residents in the 1st to 4th year of training) and non-teaching cases (experienced board-certified faculty neurosurgeons). Pain levels (VAS) and the HrQOL using the 12-item short-form health survey (SF-12) were measured at baseline, at 4 weeks and as a survey at 1 year postoperatively. In addition, data concerning the operation and the postoperative course including common complications were assessed. RESULTS: Intraoperative blood loss, length of surgery, as well as intra- and postoperative complications were similar between the study groups. Patients in both groups achieved equal results in terms of pain reduction after 4 weeks [mean VAS change -3.8 (teaching cases) vs. -3.1 (non-teaching cases), p = 0.25] and 1 year postoperatively [mean change in VAS -3.5 (teaching cases) vs. -3.37 (non-teaching cases), p = 0.84]. Teaching cases were 100 % (odds ratio of 1.00) as likely as non-teaching cases to achieve a favorable HrQOL response to surgery (p = 0.99). CONCLUSIONS: Early introduction of resident surgeons to lumbar microdiscectomy can be conducted safely within a structured and supervised educational program as it neither harms the patient nor leads to worse 1-year results. Surgical resident education may thus be implemented safely in times of rigorous working laws. However, a structured education program in which the senior surgeon gives advice, guidance and communicates cautions during each resident surgery is of paramount importance to provide high-quality patient care.

A practical laboratory study simulating the lumbar microdiscectomy: training model in fresh cadaveric sheep spine.

Laboratory training models are essential for developing and refining surgical skills prior to clinical application of spinal surgery. A simple simulation model is needed for young residents to learn how to handle instruments and to perform safe lumbar approaches. Our aim is to present a practical laboratory model using a fresh sheep lumbar spine that allows to simulate lumbar microdiscectomy in humans. The material consists of a fresh cadaveric spine from a 2-year-old sheep. The surgical steps for lumbar microdiscectomy were conducted under the magnification of the operating microscope. The cadaveric sheep spine represents a useful model to train posterior lumbar microdiscectomy.

Developing an anterior cervical diskectomy and fusion simulator for neurosurgical resident training.

BACKGROUND: Surgical simulators are useful in many surgical disciplines to augment residency training. Duty hour restrictions and increasing emphasis on patient safety and attending oversight have changed neurosurgical education from the traditional apprenticeship model. The Congress of Neurological Surgeons Simulation Committee has been developing neurosurgical simulators for the purpose of enhancing resident education and assessing proficiency. OBJECTIVE: To review the initial experience with an anterior cervical diskectomy and fusion (ACDF) simulator. METHODS: The first ACDF training module was implemented at the 2012 Congress of Neurological Surgeons Annual Meeting. The 90-minute curriculum included a written pretest, didactics, a practical pretest on the simulator, hands-on training, a written posttest, a practical posttest, and postcourse feedback. Didactic material covered clinical indications for ACDF, comparison with other cervical procedures, surgical anatomy and approach, principles of arthrodesis and spinal fixation, and complication management. Written pretests and posttests were administered to assess baseline knowledge and evidence of improvement after the module. Qualitative evaluation of individual performance on the practical (simulator) portion was included. RESULTS: Three neurosurgery residents, 2 senior medical students, and 1 attending neurosurgeon participated in the course. The pretest scores were an average 9.2 (range, 6-13). Posttest scores improved to 11.0 (range, 9-13; P = .03). CONCLUSION: Initial experience with the ACDF simulator suggests that it may represent a meaningful training module for residents. Simulation will be an important training modality for residents to practice surgical technique and for teachers to assess competency. Further development of an ACDF simulator and didactic curriculum will require additional verification of simulator validity and reliability.

Learning curve for percutaneous endoscopic lumbar discectomy depending on the surgeon's training level of minimally invasive spine surgery.

PURPOSE: To evaluate the differences of learning curve for PELD depending on the surgeon' s training level of minimally invasive spine surgery. METHODS: We retrospectively reviewed the medical records of 120 patients (surgeon A with his first 60 patients, surgeon B with his first 60 patients) with sciatica and single-level L4/5 disk herniation who underwent PELD by the two surgeons with different training level of minimally invasive spine surgery (Group A: surgeon with little professional training of PELD; Group B: surgeon with 2 years of demonstration teaching of PELD). RESULTS: Significant differences were observed in the operation time (p=0.000), postoperative hospital stay (p=0.026) and reoperation rate (p=0.050) between the two groups. In the operation time, significant differences were observed between the 1-20 patients group and 41-60 patients group in Group B (p=0.041), but there were no significant differences among the 1-20 patients group, 21-40 patients group and 41-60 patients group in Group A. In the postoperative hospital stay, the significant differences were observed in the 1-20 patients group between Group A and Group B (p=0.011). Significant differences were observed between preoperative and postoperative VAS back score, VAS leg score and JOA score. Higher improvement in the VAS leg score was observed in Group B than Group A (p=0.031). In the rate of reoperation, the significant difference was observed between the 1-20 patients group and 41-60 patients group in Group A (p=0.028) but there were no significant differences among the 1-20 patients group, 21-40 patients group and 41-60 patients group in Group B. CONCLUSIONS: The surgeons' training level of minimally invasive spine surgery was an important factor for the success of PELD, especially the demonstration teaching of PELD for the new minimally invasive spine surgeons.

Learning curve of full-endoscopic lumbar discectomy.

PURPOSE: To report the learning curve of full-endoscopic lumbar discectomy for a surgeon naive to endoscopic surgery but trained in open microdiscectomy. METHODS: From July 2006 to July 2009, 57 patients underwent full-endoscopic lumbar discectomy and 66 underwent open microdiscectomy. The clinical results were evaluated with a visual analog scale (VAS) and the Oswestry Disability Index (ODI). Spearman's coefficient of rank correlation (rho) was used to assess the learning curves for the transforaminal and interlaminar procedures of full-endoscopic lumbar discectomy. RESULTS: After full-endoscopic lumbar discectomy, the VAS and ODI results of the patients followed up were comparable with those of open microdiscectomy. A steep learning curve was observed for the transforaminal procedure, but not the interlaminar procedure. CONCLUSIONS: The learning curve of the transforaminal approach was steep and easy to learn, while the learning curve of the interlaminar approach was flat and hard to master.

Reducing the cost and frequency of explantations associated with single-level anterior diskectomy and fusion at a single institution through education.

STUDY DESIGN: We prospectively evaluated the costs/frequency of explanted instrumentation (devices implanted but removed prior to closure) for all single-level anterior diskectomy (1-ADF) procedures performed in 2010 at a single institution before and after surgeon education. OBJECTIVE: To determine whether surgeon education would reduce the costs/frequency of explantation for 1-ADF. SUMMARY OF BACKGROUND DATA: In 2009, we reported that the cost of explanted devices was 9.2% of the cost of implanted devices. METHODS: The costs/frequencies of explantation for 1-ADF performed in 2010 at the same institution by the same surgeons were analyzed before and after surgeon education. From January through April, surgeons were unaware of concerns regarding explantation. At the end of April 2010, spinal surgeons were educated about explantation costs/frequency at 2 meetings. Explantation costs/frequencies for the first 4 months of 2010 were compared with those for the last 8 months as well as with the results from 2009. RESULTS: Prior to surgeon education, instrumentation was explanted in 45.5% of the cases, whereas after education explantation occurred in 16% of the cases. The explantation rate (the number of explanted devices as a percentage of implanted devices) was lower after education for screws (12.5% vs. 7.7%), plates (9.4% vs. 0%), and allograft spacers (7.1% vs. 2.9%), and lower than for rates from 2009. In 2010, the overall cost of explanted devices as a percentage of implanted devices was also lower after surgeon education (5.8%) than before surgeon education in 2010 (20.0%) or 2009 (9.2%). CONCLUSION: The frequency and cost of explanted instrumentation used to perform 1-ADF were reduced through surgeon education.

Web-based audiovisual patient information system--a study of preoperative patient information in a neurosurgical department.

BACKGROUND: In the current climate of increasing awareness, patients are demanding more knowledge about forthcoming operations. The patient information accounts for a considerable part of the physician's daily clinical routine. Unfortunately, only a small percentage of the information is understood by the patient after solely verbal elucidation. To optimise information delivery, different auxiliary materials are used. METHODS: In a prospective study, 52 consecutive stationary patients, scheduled for an elective lumbar disc operation were asked to use a web-based audiovisual patient information system. A combination of pictures, text, tone and video about the planned surgical intervention is installed on a tablet personal computer presented the day before surgery. All patients were asked to complete a questionnaire. RESULTS: Eighty-four percent of all participants found that the audiovisual patient information system lead to a better understanding of the forthcoming operation. Eighty-two percent found that the information system was a very helpful preparation before the pre-surgical interview with the surgeon. Ninety percent of all participants considered it meaningful to provide this kind of preoperative education also to patients planned to undergo other surgical interventions. Eighty-four percent were altogether "very content" with the audiovisual patient information system and 86% would recommend the system to others. CONCLUSIONS: This new approach of patient information had a positive impact on patient education as is evident from high satisfaction scores. Because patient satisfaction with the informed consent process and understanding of the presented information improved substantially, the audiovisual patient information system clearly benefits both surgeons and patients.

Spine surgery training and competence of European neurosurgical trainees.

BACKGROUND: Little is known about the nature of spine surgery training received by European neurosurgical trainees during their residency and the level of competence they acquire in dealing with spinal disorders. METHODS: A three-part questionnaire entailing 32 questions was devised and distributed to the neurosurgical trainees attending the EANS (European Association of Neurosurgical Societies) training courses of 2004. RESULTS: Of 126 questionnaires, 32% were returned. The majority of trainees responding to the questionnaire were in their final (6(th)) year of training or had completed their training (60.3% of total). Spinal surgery training in European residency programs has clear strengths in the traditional areas of microsurgical decompression for spinal stenosis and disc herniation (77-90% competence in senior trainees). Deficits are revealed in the management of spinal trauma (34-48% competence in senior trainees) and spinal conditions requiring the use of implants and anterior approaches, with the exception of anterior cervical stabilisation. CONCLUSIONS: European neurosurgical trainees possess incomplete competence in dealing with spinal disorders. EANS trainees advocate the development of a postresidency spine subspecialty training program.

Spinal surgeons' learning curve for lumbar microendoscopic discectomy: a prospective study of our first 50 and latest 10 cases.

BACKGROUND: Microendoscopic discectomy (MED) is a minimally invasive operation that allows rapid recovery from surgery for lumbar disc herniation, but has replaced traditional open surgery in few hospitals because most surgeons avoid its long learning curve. We evaluated the effectiveness and safety of lumbar MED at stages of spinal surgeons' learning curve. METHODS: Fifty patients receiving MED from June 2002 to February 2003 were divided into chronological groups of ten each: A - E. The control group F was ten MED patients treated later by the same medical team (September - October 2006). All operations were performed by the same team of spinal surgeons with no MED experience before June 2002. We compared groups by operation time, blood loss, complications and need for open surgery after MED failure. RESULTS: Operation times by group were: A, (107 +/- 14) minutes; B, (85 +/- 13) minutes; C, (55 +/- 19) minutes; D, (52 +/- 12) minutes; E, (51 +/- 13) minutes; and F, (49+/- 15) minutes. Blood loss were: A, (131 +/- 73) ml; B, (75 +/- 20) ml; C, (48 +/- 16) ml; D, (44 +/- 17) ml; E, (45 +/- 18) ml; and F, (45 +/- 16) ml. Both operation time and blood loss in groups C, D, E and F were smaller and more stable compared with groups A and B. Japanese Orthopedic Association assessment (JOA) score of each group in improvement rate immediately and one year after operation were as follows (in percentage): A, (79.8 +/- 8.8)/(89.8 +/- 7.7); B, (78.6 +/- 8.5)/(88.5 +/- 7.8); C, (80.8 +/- 11.3)/(90.8 +/- 6.7); D, (77.7 +/- 11.4)/(88.9 +/- 9.3); E, (84.0 +/- 8.7)/(89.6 +/- 9.0); and F, (77.8 +/- 11.6)/(86.9 +/- 8.4). Groups showed no statistical difference in improvement rates. Complications developed in three patients in group A, two in group B, and none in the other groups. CONCLUSIONS: Spinal surgeons performing MED become proficient after 10 - 20 operations, when their skill becomes fairly sophisticated. Patients' improvement rate is the same regardless of surgeons' phase of learning curve.

Operative results and learning curve: microscope-assisted tubular microsurgery for 1- and 2-level discectomies and laminectomies.

OBJECT: The authors present their clinical results and the learning curve associated with the use of tubular retractors for 1- and 2-level lumbar microscope-assisted discectomies and laminectomies. METHODS: The study involves a retrospective and prospective analysis of 230 patients who underwent noninstrumented minimally invasive procedures for degenerative lumbar spinal disease between 2004 and 2007. Data on patient demographic characteristics and operative results, including length of stay, blood loss, operative times, and surgical complications were collected. Clinical outcomes were assessed based on pre- and postoperative Visual Analog Scale scores, Oswestry Disability Index values, and the Macnab outcome scale scores. RESULTS: The results showed characteristic differences in blood loss and operating times between 1- and 2-level procedures and between discectomies and laminectomies. A significant learning curve was seen by a decrease in operating time for 1-level discectomies and 2-level laminectomies. Major complications were not observed. CONCLUSIONS: The use of tubular retractors for microsurgical decompression of degenerative spinal disease is a safe and effective treatment modality. As with other techniques, minimally invasive procedures are associated with a significant learning curve. As surgeons become more comfortable with the procedure, its applications can be expanded to include, for example, spinal instrumentation and deformity correction.

Video-assisted thoracoscopic surgery in idiopathic scoliosis: evaluation of the learning curve.

STUDY DESIGN: Retrospective review of patients with idiopathic scoliosis who underwent same-day or staged anterior and posterior spinal fusion and segmental spinal instrumentation. OBJECTIVE: Evaluation of our learning curve with video-assisted thoracoscopic surgery (VATS) with respect to operative time, blood loss, and complications in patients with idiopathic scoliosis. SUMMARY OF BACKGROUND DATA: VATS is a minimally invasive alternative to thoracotomy in the management of idiopathic scoliosis. An increased or steep learning curve has been described in the initial application of this technique. METHODS: We began performing VATS in 1998. We compared our first 25 consecutive VATS patients (Group 2) and subsequent 28 consecutive VATS patients (Group 3) to our previous 16 consecutive patients (Group 1) with a thoracotomy (1991-1998) for idiopathic scoliosis. Training at a sponsored regional course was obtained before performing our first VATS procedure. RESULTS: VATS allowed more disc to be excised in Group 2 (4.5 +/- 1, 5.7 +/- 1, and 4.4 +/- 1 discs in Group 1, Group 2, and Group 3, respectively) and significantly decreased the anterior operative time (215 +/- 33, 260 +/- 56, and 177 +/- 47 minutes) and time per individual disc excision (50 +/- 13, 47 +/- 12, and 41 +/- 12 minutes), while providing comparable correction of the thoracic deformity (67% +/- 12%, 66% +/- 10%, and 70% +/- 13% correction). There was no increase in estimated intraoperative anterior blood loss (228 +/- 213, 183 +/- 136, and 211 +/- 158 mL), estimated blood loss per disc excised (51 +/- 42, 34 +/- 29 and 48 +/- 37 mL), or complications in the VATS groups. Complications were primarily pulmonary and resolved with medical therapy. Postoperative chest tube drainage (855 +/- 397, 462 +/- 249, and 561 +/- 261 mL) and total perioperative anterior blood loss (1083 +/- 507, 647 +/- 309, and 773 +/- 308 mL) were significantly decreased in the VATS groups, but this was attributed to the use of Amicar. CONCLUSIONS: VATS is an effective procedure for anterior spinal fusion in idiopathic scoliosis. The learning curve is short, provided appropriate training is obtained.

Histomorphometric assessment of thoracoscopically assisted anterior release in a porcine model: safety and completeness of disc discectomy with surgeon learning curve.

STUDY DESIGN: A retrospective study using histomorphometric analysis to quantify the percentage of discectomy following thoracoscopic anterior release and fusion in a porcine model. OBJECTIVE: To investigate the safety and completeness of disc and endplate removal with respect to the learning curve of the surgeon in a porcine thoracoscopic anterior fusion model. SUMMARY OF BACKGROUND DATA: The thoracoscopic approach has been used to perform an anterior release and fusion before an open posterior instrumentation, however, there is concern that the technique may not provide sufficient visualization or exposure to perform safely and completely. METHODS: A total of 32 pigs (160 discs) were assigned to 2 groups (early experience, n = 16; late experience, n = 16), and underwent 5 level thoracoscopic anterior release followed by anterior instrumentation and fusion from T5 to T10. At 4 months after surgery, the spines were harvested, and each discectomy disc was histomorphometrically analyzed to determine the percentage of disc excision and amount of endplate removal. RESULTS: There were no significant differences in the percent disc excision between the early (67% +/- 11%) and late groups (69% +/- 10%). Greater than 50% of the disc was excised in 151 of 160 discectomies (94%). Both superior and inferior endplates were resected in 92 of 160 disc levels (57%). The amount of endplate removal had improved over time in both early and late groups (P < 0.0001). The histologic examination revealed no evidence for posterior longitudinal ligament disruption or spinal canal encroachment in any disc. CONCLUSIONS: Video-assisted thoracoscopic discectomy is safe and allows for a significant amount of disc material excision. This study did not demonstrate a learning curve with respect to the amount of disc material excised, but a learning curve was seen for endplate excision.