Volume-Outcome Relationship After 1 and 2 Level Anterior Cervical Discectomy and Fusion

How Much Experience is Required to Acquire the Skills to Independently Perform Spine Surgery? What Milestones are Needed for Successful Surgery?

Purpose

To assess the number of surgeries needed to acquire the necessary skills to perform spine surgery independently.

Patients and Methods

A questionnaire on 12 different spinal procedures was sent to orthopedic surgeons affiliated with the spine teams of orthopedic departments at either the Akita University or Sapporo Medical University. Participants were asked to identify whether they (A) could independently perform each procedure, (B) could perform each procedure with the assistance of a senior doctor, or (C) were unable to perform each procedure. Those whose response was (A) were asked how many surgeries were required to acquire the necessary skills. Those who responded to (B) or (C) were asked how many surgeries they believed were required to acquire the skills necessary to operate independently. Participants also responded to 10 questions on surgical training techniques and rated the usefulness of each method.

Results

A total of 55 spine surgeons responded to the questionnaire. Group A required significantly fewer surgeries in the following categories to become independent than required Group C: upper cervical spine surgery (7.3/19.3), anterior cervical decompression/fusion (6.7/28.8), posterior cervical decompression/fusion (9.5/27.3), lumbar discectomy (12.6/26.7), endoscopic lumbar discectomy (10.2/24.2), spinal tumor resection (6.5/37.2), and spinal kyphosis surgery (10.3/32.3). Over 80% of participants responded that the following were effective methods: "surgeries where a senior doctor is the main surgeon, and the respondent is the assistant and observer"; "surgeries where the respondent is the main surgeon, and a senior doctor is an assistant"; "self-study using surgery manuals, articles, and textbooks"; and "training through video surgery sessions".

Conclusion

Surgeons who do not perform specific procedures independently require more surgical experience than those who operate independently. Our results may help develop more efficient training methods for spine surgeons.

Increased Surgeon-specific Experience and Volume is Correlated With Improved Clinical Outcomes in Lumbar Fusion Patients

STUDY DESIGN

The present study design was that of a single center, retrospective cohort study to evaluate the influence of surgeon-specific factors on patient functional outcomes at 6 months following lumbar fusion. Retrospective review of a prospectively maintained database of patients who underwent neurosurgical lumbar instrumented arthrodesis identified the present study population.

OBJECTIVE

This study seeks to evaluate surgeon-specific variable effects on patient-reported outcomes such as Oswestry Disability Index (ODI) and the effect of North American Spine Society (NASS) concordance on outcomes in the setting of variable surgeon characteristics.

SUMMARY OF BACKGROUND DATA

Lumbar fusion is one of the fastest growing procedures performed in the United States. Although the impact of surgeon-specific factors on patient-reported outcomes has been contested, studies examining these effects are limited.

METHODS

This is a single center, retrospective cohort study analyzing a prospectively maintained database of patients who underwent neurosurgical lumbar instrumented arthrodesis by 1 of 5 neurosurgery fellowship trained spine surgeons. The primary outcome was improvement of ODI at 6 months postoperative follow-up compared with preoperative ODI.

RESULTS

A total of 307 patients were identified for analysis. Overall, 62% of the study population achieved minimum clinically important difference (MCID) in ODI score at 6 months. Years in practice and volume of lumbar fusions were statistically significant independent predictors of MCID ODI on multivariable logistic regression ( P =0.0340 and P =0.0343, respectively). Concordance with evidence-based criteria conferred a 3.16 (95% CI: 1.03, 9.65) times greater odds of achieving MCID.

CONCLUSION

This study demonstrates that traditional surgeon-specific variables predicting surgical morbidity such as experience and procedural volume are also predictors of achieving MCID 6 months postoperatively from lumbar fusion. Independent of surgeon factors, however, adhering to evidence-based guidelines can lead to improved outcomes.

Describing the spine surgery learning curve during the first two years of independent practice

Retrospective cohort studyTo characterize the learning curve of a spine surgeon during the first 2 years of independent practice by comparing to an experienced colleague. To stratify learning curves based on procedure to evaluate the effect of experience on surgical complexity.The learning curve for spine surgery is difficult to quantify, but is useful information for hospital administrators/surgical programs/new graduates, so appropriate expectations and accommodations are considered.Data from a retrospective cohort (2014-2016) were analyzed at a quaternary academic institution servicing a geographically-isolated, mostly rural area. Procedures included anterior cervical discectomy and fusion, posterior cervical decompression and stabilization, single and 2-level posterior lumbar interbody fusion, lumbar discectomy, and laminectomy. Data related to patient demographics, after-hours surgery, and revision surgery were collected. Operative time was the primary outcome measure, with secondary measures including cerebrospinal fluid leak and early re-operation. Time periods were stratified into 6 month quarters (quarter [Q] 1-Q4), with STATA software used for statistical analysis.There were 626 patients meeting inclusion criteria. The senior surgeon had similar operative times throughout the study. The new surgeon demonstrated a decrease in operative time from Q1 to Q4 (158 minutes-119 minutes, P < .05); however, the mean operative time was shorter for the senior surgeon at 2 years (91 minutes, P < .05). The senior surgeon performed more revision surgeries (odds ratio [OR] 2.5 [95% confidence interval [CI] 1.7-3.6]; P < .001). Posterior interbody fusion times remained longer for the new surgeon, while laminectomy surgery was similar to the senior surgeon by 2 years. There were no differences in rates of cerebrospinal fluid leak (OR 1.2 [95% CI 0.6-2.5]; P > .05), nor reoperation (OR 1.16 [95% CI 0.7-1.9]; P > .05) between surgeons.A significant learning curve exists starting spine practice and likely extends beyond the first 2 years for elective operations.

Analyzing the Correlation Between Surgeon Experience and Patient Length of Hospital Stay

Introduction  Many clinical, social, and even economic factors have been extensively analyzed in the literature and shown to influence the length of stay (LOS) after spinal procedures. However, surgeon's experience was mostly examined relative to a learning curve and not regarding the time in practice. The primary objective of this study was to determine the effect of one surgeon's experience on the LOS in patients undergoing one- to two-level transforaminal lumbar interbody fusions (TLIFs). Materials and Methods  The study design was a retrospective cohort study of hospital discharge data. The cohort was comprised of 240 consecutive patients who had undergone open one- or two-level elective TLIF procedures for lumbar degenerative disc disease. The primary predictor was the surgeon's experience based upon the years of practice. The primary outcome was LOS, which was controlled by the discharge criteria that remained consistent throughout the study. Results  Based on the Poisson regression model, it can be inferred that the LOS is not significantly associated with a surgeon's experience (Pr(>|t|) = 0.8985, CI: -0.5825 to 0.5114) while controlling for all other variables. Other independent factors did seem to significantly influence patients' LOS, including the admission type (Pr(>|t|) = 9.637^-08, CI: -0.8186 to -0.3786), the number of TLIF levels (Pr(>|t|) = 1.721^-06, CI: 0.0606 to 0.1446), the Clavien-Dindo ( Pr(>|t|) = 0, CI: 0.1489 to 0.1494), the American Society of Anesthesiologists (ASA) physical status classification scores (Pr(>|t|) = 4.878^-3, CI: 0.0336 to 0.1880), and being discharged to skilled nursing facility (Pr(>|t|) = 3.44^-2, CI: 0.0127 to 0.3339). Conclusions Based upon the years in practice, surgeon experience was not associated with length of hospitalization and estimated blood loss during surgery in patients undergoing one- and two-level TLIF surgeries. However, while controlling for all other variables, the surgeon's experience and surgical time had a highly significant correlation. The study results clearly demonstrated efficiency, but we did not identify a clear correlation between LOS and surgeon experience overtime suggesting that other factors are likely contributing to such outcome. The average LOS is a complex measure of healthcare resource use and hospital discharge policy or other variables are likely having more effect on LOS than individual surgeons' preferences.

Complications of anterior cervical spine surgery: a systematic review of the literature

The anterior approach to the cervical spine is commonly utilized for a variety of degenerative, traumatic, neoplastic, and infectious indications. While many potential complications overlap with those of the posterior approach, the distinct anatomy of the anterior neck also presents a unique set of hazards. We performed a systematic review of the literature to assess the etiology, presentation, natural history, and management of these complications. Following the guidelines of the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA), a PubMed search was conducted to evaluate clinical studies and case reports of patients who suffered a complication of anterior cervical spine surgery. The search specifically included articles concerning adult human subjects, written in the English language, and published from 1989 to 2019. The PubMed search yielded 240 articles meeting our criteria. The overall rates of complications were as follows: dysphagia 5.3%, esophageal perforation 0.2%, recurrent laryngeal nerve palsy 1.3%, infection 1.2%, adjacent segment disease 8.1%, pseudarthrosis 2.0%, graft or hardware failure 2.1%, cerebrospinal fluid leak 0.5%, hematoma 1.0%, Horner syndrome 0.4%, C5 palsy 3.0%, vertebral artery injury 0.4%, and new or worsening neurological deficit 0.5%. Morbidity rates in anterior cervical spine surgery are low. Nevertheless, the unique anatomy of the anterior neck presents a wide variety of potential complications involving vascular, aerodigestive, neural, and osseous structures.

Evolution in Surgical Approach, Complications, and Outcomes in an Adult Spinal Deformity Surgery Multicenter Study Group Patient Population

STUDY DESIGN

Retrospective review of a prospectively collected multicenter database.

OBJECTIVES

To evaluate the evolution of surgical treatment strategies, complications, and patient-reported outcomes for adult spinal deformity (ASD) patients.

SUMMARY OF BACKGROUND DATA

ASD surgery is associated with high complication rates. Evolving treatment strategies may reduce these risks.

METHODS

Adult patients undergoing ASD surgery from 2009 to 2016 were analyzed (n = 905). Preoperative and surgical parameters were compared across years. Subgroup analysis of 436 patients with minimum two-year follow-up was also performed.

RESULTS

From 2009 to 2016, there was a significant increase in the mean preoperative age (52 to 63.1, p < .001), body mass index (26.3 to 32.2, p = .003), Charlson Comorbidity index (1.4 to 2.2, p < .001), rate of previous spine surgery (39.8% to 53.1%, p = .01), and baseline disability (visual analog scale [VAS] back and leg pain) scores (p < .01), Oswestry Disability Index, and 22-item Scoliosis Research Society Questionnaire scores (p < .001). Preoperative Schwab sagittal alignment modifiers and overall surgical invasiveness index were similar across time. Three-column osteotomy utilization decreased from 36% in 2011 to 16.7% in 2016. Lateral lumbar interbody fusion increased from 6.4% to 24.1% (p = .004), anterior lumbar interbody fusion decreased from 22.9% to 16.7% (p = .043), and transforaminal lumbar interbody fusion/posterior lumbar interbody fusion utilization remained similar (p = .448). Use of recombinant human bone morphogenetic protein-2 (rhBMP-2) in 2012 was 84.6%, declined to 58% in 2013, and rebounded to 76.3% in 2016 (p = .006). Tranexamic acid use increased rapidly from 2009 to 2016 (13.3% to 48.6%, p < .001). Two-year follow-up sagittal vertical axis, pelvic tilt, pelvic incidence-lumbar lordosis, and maximum Cobb angles were similar across years. Intraoperative complications decreased from 33% in 2010 to 9.3% in 2016 (p < .001). Perioperative (<30 days, <90 days) complications peaked in 2010 (42.7%, 46%) and decreased by 2016 (24.1%, p < .001; 29.6%, p = .007). The overall complication rate decreased from 73.2% in 2008-2014 patients to 62.6% in 2015-2016 patients (p = .03). Two-year health-related quality of life outcomes did not significantly differ across the years (p > .05).

CONCLUSIONS

From 2009 to 2016, despite an increasingly elderly, medically compromised, and obese patient population, complication rates decreased. Evolving strategies may result in improved treatment of ASD patients.

LEVEL OF EVIDENCE

Level IV.

Relationship between surgeon volume and outcomes in spine surgery: a dose-response meta-analysis

Background

The relationship between surgeon volume and outcomes in spine surgery is unclear and published studies report inconsistent results. Therefore, a dose-response meta-analysis was conducted to clarify the influence of surgeon volume on outcomes in spine surgery.

Methods

PubMed, Embase, and The Cochrane Library were systematically searched without language limitation for observational studies which investigated the relationship between surgeon volume and outcomes in spine surgery. The primary outcome was postoperative morbidity and the secondary outcomes consisted of mortality, length of hospital stay, readmission, and hospital costs. For binary variable and continuous variable, odds ratios (ORs) with 95% CIs and weighted mean differences (WMDs) with 95% CIs were pooled respectively. Additionally, a dose-response meta-analysis was performed for the primary outcome.

Results

Eleven studies with 1,986,545 patients were included in the current meta-analysis. Pooled estimate indicated that a higher surgeon volume was associated with lower postoperative morbidity (OR, 0.62; 95% CI: 0.52-0.75; I²=93.9%), lower mortality (OR, 0.76; 95% CI: 0.66-0.87; I²=0), shorter length of hospital stay (WMD, -7.07; 95% CI: -7.08 to -7.06; I²=100%), less readmission (OR, 0.78; 95% CI: 0.72-0.85; I²=93.1%), and lower hospital costs (WMD, -25,497.47; 95% CI: -25,528.43 to -25,466.51; I²=100%). Dose-response analysis suggested a nonlinear relationship between surgeon volume and postoperative morbidity (P for nonlinearity less than 0.00001).

Conclusions

The current evidence indicate that higher surgeon volume is associated with lower morbidity and mortality, shorter length of hospital stay, less readmission, and lower hospital costs in spine surgery.

Recurrent Laryngeal Nerve Palsy Is More Frequent After Secondary than After Primary Anterior Cervical Discectomy and Fusion: Insights from a Registry of 525 Patients

BACKGROUND

Recurrent laryngeal nerve (RLN) palsy is a common complication after anterior cervical discectomy and fusion (ACDF) and usually manifests with dysphagia, hoarseness, and respiratory difficulties. Next to proven risk factors, such as age and multilevel procedures, RLN palsy has been speculated to occur more frequently after secondary ACDF procedures.

METHODS

We analyzed a prospective registry of all consecutive patients undergoing zero-profile ACDF for disc herniation, myelopathy, or stenosis. RLN palsy was defined as persistent patient self-reported dysphagia, hoarseness, or respiratory problems without other identifiable causes. RLN palsy was assessed at scheduled 6-week telephone interviews.

RESULTS

Among 525 included patients, 511 primary and 40 secondary ACDF procedures were performed. Hoarseness was present in 12 (2.2%) cases, whereas dysphagia and respiratory difficulties both occurred in 3 (0.5%) cases. Overall incidence of RLN palsy was 2% after primary procedures and 8% after secondary procedures (P = 0.017). These rates are in line with the peer-reviewed literature, and the difference remained significant after controlling for confounders in a multivariate model (P = 0.033). Other reported risk factors, such as age, sex, surgical time, and multilevel procedures, had no relevant effect (P > 0.05).

CONCLUSIONS

Based on our data and other published series in the literature, RLN palsy may occur more frequently after secondary ACDF procedures with a clinically relevant effect size. There is a striking lack of uniformity in methods and reporting in research on RLN injury.