Opioid Prescribing Habits of General Versus Pediatric Surgeons After Uncomplicated Laparoscopic Appendectomy

Implementation of Guidelines Limiting Postoperative Opioid Prescribing at a Children's Hospital

OBJECTIVES

Variability in opioid-prescribing practices after common pediatric surgical procedures at our institution prompted the development of opioid-prescribing guidelines that provided suggested dose limitations for narcotics. The aims of this study were to improve opioid prescription practices through implementation of the developed guidelines and to assess compliance and identify barriers preventing guideline utilization.

METHODS

We conducted a single-center cohort study of all children who underwent the most common outpatient general surgery procedures at our institution from August 1, 2018, to February 1, 2020. We created guidelines designed to limit opioid prescription doses based on data obtained from standardized postoperative telephone interviews. Three 6-month periods were evaluated: before guideline implementation, after guideline initiation, and after addressing barriers to guideline compliance. Targeted interventions to increase compliance included modification of electronic medical record defaults and provider educations. Differences in opioid weight-based doses prescribed, filled, and taken, as well as protocol adherence between the 3 timeframes were evaluated.

RESULTS

A total of 1033 children underwent an outpatient procedure during the 1.5-year time frame. Phone call response rate was 72.22%. There was a significant sustained decrease in opioid doses prescribed ( P < 0.0001), prescriptions filled ( P = 0.009), and opioid doses taken ( P = 0.001) after implementation, without subsequent increase in reported pain on postoperative phone call ( P = 0.96). Protocol compliance significantly improved (62.39% versus 83.98%, P < 0.0001) after obstacles were addressed.

CONCLUSIONS

Implementation of a protocol limiting opioid prescribing after frequently performed pediatric general surgery procedures reduced opioids prescribed and taken postoperatively. Interventions that addressed barriers to application led to increased protocol compliance and sustained decreases in opioids prescribed and taken without a deleterious effect on pain control.

Pain Management Throughout Pediatric Laparoscopic Appendectomy: A Systematic Review

Opioid-related fatalities are a leading cause of accidental death in the United States. Appendicitis is a common cause of abdominal pain in children and adolescents. The management of pain throughout the laparoscopic appendectomy (LA) in the pediatric population is a critical concern. This study aimed to evaluate trends in analgesic use and patient satisfaction following LA, with a focus on reducing the reliance on opioids for pain management. From 2003 to 2023, 18258 articles were filtered for all types of analgesic use with LA. The publications were screened using Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, and 19 studies were included for analysis and review. The study included peer-reviewed experimental and observational studies involving individuals under 18 years. Pain management strategies varied across studies, involving a combination of analgesics, nerve blocks, and wound infiltrations. Analgesics such as acetaminophen, non-steroidal anti-inflammatory drugs (NSAIDs), and opioids were administered before and after surgery. Some studies implemented patient-controlled analgesia (PCA) pumps. Other studies explored non-pharmacological interventions like magnetic acupuncture. The results showed a reduction in the need for postoperative analgesics in patients treated with LA, particularly when using non-opioid medications and novel analgesic techniques. Pediatric patients who received gabapentin reported lower opioid use, shorter hospital stays, and high satisfaction rates. However, the reliance on opioids remained significant in some cases, particularly among patients with peritonitis who required more morphine. Pain management in pediatric patients is multifaceted, involving preoperative and postoperative analgesics, nerve blocks, and PCA pumps. Efforts to improve pain management following pediatric LA while reducing opioid reliance are essential in the context of the ongoing opioid epidemic. The findings from this study highlight the potential benefits of non-opioid analgesics, nerve blocks, and alternative methods for managing postoperative pain in <18 appendectomy patients. Further research and standardization of pain management protocols are needed to ensure optimal patient outcomes and minimize the risk of opioid-related complications.

Difference in Postoperative Outcomes and Perioperative Resource Utilization Between General Surgeons and Pediatric Surgeons: A Systematic Review

Background: Both general surgeons (GS) and pediatric surgeons (PS) perform a high volume of appendectomies in pediatric patients, but there is a paucity of data on these outcomes based on surgeon training. We performed a systematic review and meta-analysis to compare postoperative outcomes and perioperative resource utilization for pediatric appendectomies.Methods: We searched PubMed to identify articles examining the association between surgeon specialization and outcomes for pediatric patients undergoing appendectomies. Study selection, data extraction, risk of bias assessment, and quality assessment were performed by one reviewer, with another reviewer to resolve discrepancies.Results: We identified 4799 articles, with 98.4% (4724/2799) concordance after initial review. Following resolution of discrepancies, 16 studies met inclusion criteria. Of the studies that reported each outcome, GS and PS demonstrated similar rates of readmission within 30 days (pooled RR 1.61 95% CI 0.66, 2.55) wound infections (pooled RR 1.07, 95% CI .55, 1.60), use of laparoscopic surgery (pooled RR 1.87, 95% CI .21, 3.53), postoperative complications (pooled RR 1.40, 95% CI .83, 1.97), use of preoperative imaging (pooled RR .98,95% CI .90, 1.05), and intra-abdominal abscesses (pooled RR .80, 95% CI .03, 1.58). Patients treated by GS did have a significantly higher risk of negative appendectomies (pooled RR 1.47, 95% CI 1.10, 1.84) when compared to PS.Discussion: This is the first meta-analysis to compare outcomes for pediatric appendectomies performed by GS compared to PS. Patient outcomes and resource utilization were similar among PS and GS, except for negative appendectomies were significantly more likely with GS.

Patient-Reported Outcomes in Pain Management After Ambulatory Pediatric General and Urologic Surgery

BACKGROUND

Many studies evaluating opioid stewardship interventions' effects on postoperative pain rely on emergency department (ED) visits or readmissions, but patient-reported pain scores represent a more complete picture of the postoperative experience. This study compares patient-reported pain scores after ambulatory pediatric and urologic procedures and the effect of an opioid stewardship intervention that nearly eliminated the use of outpatient narcotics.

METHODS

This is a retrospective comparative study including 3173 pediatric patients who underwent ambulatory procedures from 2015 to 2019, during which there was an intervention to reduce narcotic prescriptions. Postoperative day one phone calls assessed pain levels using a four-point scale (no pain, mild pain, moderate pain controlled with medication, or severe pain uncontrolled with medication). We quantified the proportion of patients prescribed opioids pre-versus post-intervention and compared pain scores for patients receiving opioid versus non-opioid regimens.

RESULTS

Opioid prescription rates demonstrated a 6.5-fold reduction after opioid stewardship efforts. The majority of patients (2838) received non-opioids, with only 335 patients receiving opioids. Opioid patients reported moderate/severe pain slightly more than non-opioid patients (14.1% vs. 10.4%, p = 0.04). On by-procedure analyses, there were no subgroups in which non-opioid patients reported significantly higher pain scores.

CONCLUSIONS

Non-opioid postoperative pain regimens appear to be effective, with only 10.4% of patients reporting moderate/severe pain after ambulatory procedures. Future studies assessing patient-reported outcomes are necessary to optimize pain control for all patients and to determine whether there is ever an indication for opioid prescription after ambulatory general pediatric or urologic surgery.

TYPE OF STUDY

Retrospective comparative study.

LEVEL OF EVIDENCE

Level III.

Unused opioid prescription prevalence after pediatric ambulatory surgery: a survey study

Background

Surgery is a risk factor for opioid initiation, persistent use, and subsequent misuse in pediatric patients. The objective of this study was to assess the rate of postoperative opioid prescribing and extent of unused opioid prescriptions on the first postoperative day after pediatric ambulatory surgery.

Methods

A telephone survey was administered on postoperative day 1 (POD1) to guardians of all pediatric patients who underwent ambulatory surgery at a single medical center. Participants were asked whether postoperative opioids were prescribed, and, if yes, whether they were currently taking them. Multivariable logistic regression was used to assess factors associated with postoperative opioid prescribing and unused opioids on POD1.

Results

Of 1344 pediatric patients who underwent ambulatory surgical procedures, 849 (63.1%) guardians responded to the survey. 275 (32.4%) were prescribed postoperative opioids, and 164 (59.6%) reported not taking opioids on POD1. The highest rates of unused opioid prescriptions were from orthopedic and plastic surgery services (28% and 29%, respectively). Governmental insurance status predicted having unused opioids (OR 0.59, CI 0.35–0.97).

Conclusions

Unused opioid prescriptions were prevalent in this pediatric ambulatory surgical population. Opportunities remain to streamline opioid prescribing in pediatric patients undergoing ambulatory surgical procedures.

Characterizing opioid prescribing to adolescents at time of discharge from a pediatric hospital over a five-year period

PURPOSE

To characterize opioid prescribing over a 5-year period to adolescents upon discharge from one urban pediatric medical center.

DESIGN AND METHODS

A retrospective cross-sectional analysis of 4354 adolescents discharged with a pain medication after an admission of ≤5 days between January 2015 and December 2019 was performed. Two outcome groups, based on the analgesics prescribed at discharge, were compared: those discharged with a prescription for a non-opioid only and those discharged with an opioid prescription. The association between year of discharge and receipt of opioid, while adjusting for relevant demographic and clinical characteristics, was also explored.

RESULTS

Approximately 64% of the sample was discharged with an opioid prescription. Of those, the median daily dosage was 45.0 morphine milligram equivalents (MME) [IQR: 32.4, 45.0]. Year of discharge was associated with decreased odds of receiving an opioid when adjusting for age, race, sex, insurance, pain scores, opioid exposure during hospitalization, length of stay, and undergoing surgery. The odds of being discharged with an opioid decreased each year by 29% (Adjusted Odds Ratio [AOR] = 0.71, CI:0.68-0.73). Concurrently, the proportion of patients discharged with nonopioid pain medication increased from 25% of adolescent patients in 2015 to 50% in 2019.

CONCLUSIONS

Overall, opioid prescribing to adolescents at time of discharge decreased over time in our sample.

PRACTICE IMPLICATIONS

While prescribing has decreased opioid analgesics are dispensed to young patients. Risk of opioid use disorder and overdose is rare in this population, but adolescence is good opportunity for nursing to promote safe prescribing and analgesic use.

Evaluation of Postoperative Pain Management Using an Opioid-Sparing Protocol in Pediatric Surgical Patients

BACKGROUND

Since the 1990s, the U.S. has faced increasing rates of opioid overuse, misuse, and overdose deaths. To combat the opioid epidemic, there have been national initiatives to limit prescribing of opioids. At our institution, we implemented an opioid-sparing protocol in pediatric surgical patients and sought to evaluate its impact on postoperative opioid prescribing patterns.

METHODS

A retrospective chart review of the electronic medical record was performed for 9- to 18-year-old patients who underwent a laparoscopic appendectomy or cholecystectomy before and after the implementation of an opioid-sparing protocol. Data on postoperative opioids administered during the hospitalization and prescribed at discharge, postoperative pain control, use of non-opioid analgesics, and safety were collected.

RESULTS

A total of 81 patient charts were analyzed. The median amount of opioids administered during hospitalization was 8 MMEs and 15 MMEs in the pre-implementation and post-implementation, respectively (P = 0.310). The median amount of opioids prescribed at discharge was 150 MMEs and 60 MMEs in the pre-implementation and post-implementation, respectively (P = 0.006). Patients reported mild pain scores throughout the hospitalization in both groups.

DISCUSSION

Among young patients who underwent laparoscopic appendectomy or cholecystectomy, the administration of opioids during hospitalization for postoperative pain was minimal. The opioid sparing protocol did not reduce the amount of inpatient postoperative opioids administered but found a decrease in the amount of opioids prescribed at discharge. The study findings identified further areas of intervention and education to optimize postoperative opioid prescribing after these common pediatric surgical procedures.

Post-Procedural Opioid Prescribing in Children: A Survey of the American Academy of Pediatrics

INTRODUCTION

North America is in the midst of an opioid epidemic. The role of pediatric surgeons and other procedural specialists in this public health crisis remains unclear. There is likely considerable variation in the use of opioid and non-opioid analgesics, but the spectrum of practice is still uncertain.

METHODS

We performed an online survey in July 2018 of the 2086 pediatric surgeons and proceduralists who were active members in the American Academy of Pediatrics. The survey inquired about practice environment, use of opioid and non-opioid pain medications, and attitudes towards the opioid epidemic.

RESULTS

178 specialists completed the survey for a response rate of 8.5%. Most respondents utilize oral acetaminophen (86%) and ibuprofen (80%) after procedures >75% of the time. Self-reported opioid prescribing increases with age after both outpatient and inpatient procedures (P < 0.001). Pediatric general surgeons prescribe opioids less frequently than other specialists, particularly after inpatient procedures. The majority of respondents (81%) believe that the opioid epidemic is a major problem but only 31% indicated that they have a major role to play.

CONCLUSIONS

There is significant variation in opioid prescribing patterns as reported by pediatric surgeons and proceduralists. Guidelines are needed to standardize the use of non-opioid analgesics and decrease reliance on opioids for outpatient and inpatient procedures.

Impact of prescription drug monitoring program mandate on postoperative opioid prescriptions in children

PURPOSE

Prescription drug monitoring programs (PDMPs) have been established to combat the opioid epidemic, but there is no data on their efficacy in children. We hypothesized that a statewide PDMP mandate would be associated with fewer opioid prescriptions in pediatric surgical patients.

METHODS

Patients < 18 undergoing inguinal hernia repair, orchiopexy, orchiectomy, appendectomy, or cholecystectomy at a tertiary children's hospital were included. The primary outcome, discharge opioid prescription, was compared for 10 months pre-PDMP (n = 158) to 10 months post-PDMP (n = 228). Interrupted time series analysis was performed to determine the effect of the PDMP on opioid prescribing.

RESULTS

Over the 20-month study period, there was an overall decrease in the rate of opioid prescriptions per month (- 3.6% change, p < 0.001). On interrupted time series analysis, PDMP implementation was not associated with a significant decrease in the monthly rate of opioid prescriptions (1.27% change post-PDMP, p = 0.4). However, PDMP implementation was associated with a reduction in opioid prescriptions of greater than 5 days' supply (- 2.7% per month, p = 0.03).

CONCLUSION

Opioid prescriptions declined in pediatric surgical patients over the study time period. State-wide PDMP implementation was associated with a reduction in postoperative opioid prescriptions of more than 5 days' duration.

Pediatric versus adult paradigms for management of adolescent injuries within a regional trauma system

BACKGROUND

We aimed to examine process and outcome indicators for adolescents with specific injury patterns managed in pediatric versus adult paradigms within the same trauma system.

METHODS

Adolescents (15-17 years old) admitted to the region's adult trauma center (ATC) or pediatric trauma center (PTC) with an abdominal injury, femur fracture or traumatic brain injury (TBI) were reviewed retrospectively. Global and injury-specific process and outcome indicators were compared.

RESULTS

Of 141 ATC and 69 PTC patients, injury patterns differed significantly with more TBI and abdominal injuries at the ATC and femur fractures at the PTC. Overall injury severity was greater at the ATC. Patients with solid organ injuries appeared more likely to undergo embolization or splenectomy at the ATC; however, higher injury grade and later time period were the only variables significantly associated with this. Computed tomography (CT) was used significantly more frequently at the ATC overall, most notable with panscanning and head CTs for major TBI. Time to operative management did not differ for patients with isolated femur fractures. Neuropsychological follow up after minor TBI was documented more often at the PTC than the ATC; there was no difference for those with more severe TBIs.

CONCLUSIONS

Management varies for adolescents between PTCs and ATCs with more exposure to radiation and less neuropsychological follow-up of less severe TBIs at the ATC. This presents distinct opportunities to identify best policies for triage and sharing of management practices within a single regional inclusive trauma system in order to optimize short and long-term outcomes for this population.

TYPE OF STUDY

Retrospective cohort.

LEVEL OF EVIDENCE

Level IV.

Opioid stewardship in pediatric surgery: Approaching zero

INTRODUCTION

In response to the opioid epidemic, we hypothesized that adequate pain control can be achieved with few, if any, opioid prescriptions at discharge following pediatric surgical procedures.

METHODS

All records for patients 0-15 years old who underwent pediatric surgical operations from December 2017 through May 2018 were reviewed. Opioids prescriptions, emergency department (ED) visits, and hospital readmissions were recorded. Postoperative pain was assessed on a scale from 0 to 10 via phone call within three days of discharge.

RESULTS

352 patients underwent 394 surgical procedures. Three patients were prescribed opioids at discharge. There were no pain-related readmissions. One patient returned to the ED owing to pain. 116 unique pain scores were obtained from 114 patients: score 0 (n = 69, 59%), 1-3 (n = 31, 27%), 4-5 (n = 11, 9%), 6-8 (n = 5, 4%), and 9-10 (n = 0, 0%). There was a positive association between pain and increasing age (r = 0.26, p = 0.005). No patients who underwent hernia repair reported a pain score greater than 3.

CONCLUSIONS

Adequate pain control at discharge after pediatric general surgical procedures can be achieved for most children with scheduled nonopioid medications only. A limited supply of opioids for analgesia after discharge may benefit small subset of patients. This strategy would help reduce opioid prevalence in the community.

TYPE OF STUDY

Retrospective cohort study.

LEVEL OF EVIDENCE

Level III.

Prescribing Habits of Providers and Risk Factors for Nonadherence to Opioid Prescribing Guidelines

BACKGROUND

The Michigan Opioid Prescribing Engagement Network introduced guidelines in October 2017 to combat opioid overprescription following various surgical procedures. We sought to evaluate changes in opioid prescribing at our academic center and identify factors associated with nonadherence to recently implemented opioid prescribing guidelines.

METHODS

This retrospective review analyzed opioid prescribing data for appendectomy, cholecystectomy, and hernia repair from January 2015 through September 2017 (pre-guidelines group) and November 2017 through December 2018 (post-guidelines group). October 2017 data were excluded to allow for guideline implementation. Opioid prescribing data were recorded as total morphine equivalents (TMEs).

RESULTS

Of 1493 cases (903 pre-vs. 590 post-guidelines), the mean TME prescribed significantly decreased post-guidelines (231.9 ± 108.6 vs. 112.7 ± 73.9 mg; P < .01). More providers prescribed within recommended limits post-guidelines (2.8% vs. 44.8%; P < .01). On multivariable analysis, independent risk factors for guideline nonadherence were the American Society of Anesthesiologists class > 2 (adjusted odds ratio [AOR]:1.65, 95% confidence interval[CI] 1.09-2.49; P = .02), general surgery vs. acute care surgery service (AOR 1.89, 95% CI 1.15-3.10; P = .01), oxycodone vs. hydrocodone (AOR:1.90, 95% CI:1.06-3.41; P = .03), and nonphysician provider vs. resident prescriber (AOR:2.10, 95% CI:1.14-3.11; P < .01).

CONCLUSIONS

Opioid prescribing significantly reduced after the adoption of opioid prescribing guidelines at our institution. Numerous factors associated with provider guideline nonadherence may identify actionable targets to minimize opioid overprescribing further.

Creating an Opioid Recommendation Card for Trainees: Methods, Use, and Impact

BACKGROUND

In academic hospitals, surgical residents write most of the postoperative prescriptions; yet, few residents are trained on postoperative analgesia. This leads to wide variability in practices and often excess opioid prescribing. We sought to create an opioid guideline pocket card for surgical residents to access when prescribing opioids postoperatively and to evaluate the impact of this initiative.

METHODS

A comprehensive literature review was conducted to generate evidence-based procedure-specific opioid recommendations; additional recommendations were formulated via consensus opinion from surgical divisions at an academic institution. A pocket-sized guideline card was developed to include these procedure-specific recommendations as well as opioid guidelines for discharges after inpatient stays, non-opioid analgesic recommendations, access to opioid safety and disposal instructions for patients discharge, an equianalgesic dosing chart, and instructions for naloxone use. The card was distributed to all General Surgery house staff at a university-affiliated hospital in the spring of 2018. Following the distribution, trainees were surveyed on their use of the card. Descriptive statistics were used to analyze the survey.

RESULTS

Of 85 trainees, 62 (72.9%) responded to the survey in full; 58% use the card regularly. Of the 27 junior resident respondents, 70.4% use the card at least monthly including 48.1% who use the card daily-to-weekly. Overall, 81.6% of residents changed their opioid-prescribing practices because of this initiative and 89.8% believe the card should continue to be distributed and used.

DISCUSSION

An evidence-based guideline card for postoperative analgesia is highly valued and utilized by surgical trainees, especially those most junior in their training.

Eliminating Opiate Prescribing for Children after Non-Perforated Appendectomy

BACKGROUND

Opiates are the traditional treatment for postoperative pain. Recognition that increased availability of opiates in the community is associated with increased addiction has led to efforts to decrease postoperative opiate distribution. However, there are concerns that without opiates, pain relief might be inadequate.

STUDY DESIGN

We analyzed opiate prescriptions to children who had undergone appendectomy during 3 time periods: before intervention (July 2012 through February 2013), after opiate prescriptions were standardized and reduced (December 2016 through December 2017), and after opiate prescriptions were eliminated (January 2018 through December 2018). We determined how many opiate prescriptions had been written and how many had been filled in each time period. Patients were contacted by phone to identify their medication use and quality of pain management.

RESULTS

Pre-intervention, 75 children underwent appendectomy, and all received opiate prescriptions, with a mean of 15 doses of oxycodone prescribed per patient. After reduction, 208 children underwent appendectomy and 30% received opiate prescriptions, for a mean of 1.5 doses of oxycodone per patient. After elimination, 270 patients underwent appendectomy and 3 patients (1.1%) received opiate prescriptions, for a mean of 0.05 doses of oxycodone per patient. Patients contacted by phone expressed no pain relief issues and no patients needed opiates later.

CONCLUSIONS

Using a stepwise process, we have eliminated the use of opiates for postdischarge pain in children undergoing laparoscopic appendectomy. This intervention has resulted in the elimination of 4,035 doses of oxycodone from the community during the study period, while ensuring that postoperative pain control has been adequate.

The Value of Shorter Initial Opioid Prescriptions: A Simulation Evaluation

BACKGROUND

During the period from 1999 to 2016, more than 350,000 Americans died from overdoses related to the use of prescription opioids. To the extent that supply is directly related to overprescribing, policy interventions aimed at changing prescriber behavior, such as the recent Centers for Disease Control and Prevention guideline, are clearly warranted. Although these could plausibly reduce the prevalence of opioid overuse and dependency, little is known about their economic and health-related impacts.

OBJECTIVE

The aim of this study was to quantify the efficacy of a policy intervention aimed at reducing the length of initial opioid prescriptions.

STUDY DESIGN AND METHODS

A Markov decision process model was fitted on a retrospective cohort of 827,265 patients, and patient cost and health trajectories were simulated over a 24-month period. The model's parameters were based on patients who received short (≤ 3 days) or long (> 7 days) initial opioid prescriptions, matched using propensity score methods.

STUDY POPULATION

All active-duty US Army soldiers from 2011 to 2014; the data contained detailed medical and administrative information on over 11 million soldier-months corresponding to 827,265 individual soldiers.

MAIN OUTCOME MEASURE

Overall costs of a policy change, quality-adjusted life-years (QALYs) gained, and $/QALY gained.

RESULTS

Over a 2-year horizon, a reassignment of 10,000 patients to short initial duration would generate a cost saving in the vicinity of $3.1 million (excluding program costs), and would also lead to an estimated 4451 additional opioid-free months, i.e. months without any opioid prescriptions.

CONCLUSION

The analysis found that efforts to change prescriber behavior can be cost effective, and further studies into the implementation of such policies are warranted.

An Evidence-Based Guideline Supporting Restricted Opioid Prescription after Pediatric Appendectomy

BACKGROUND/PURPOSE

Surgeon overprescription of opioids is a modifiable contributor to the opioid epidemic. No clear guidelines exist for prescribing opioids to younger patients after surgery. We sought to determine postoperative opioid needs in pediatric/young adult patients after laparoscopic appendectomy.

METHODS

Patients 5-20 years old who underwent laparoscopic appendectomy were included for study. All consented patients underwent chart review and were additionally called for an attempted interview. Caregivers were queried on analgesic use and adequacy of pain relief. The main outcome measures were: quantity of opioid used, desire for an opioid, presence of pain ≥4/10, and need for follow-up/call owing to pain. All opioids were converted into morphine milligram equivalents (MME).

RESULTS

Seventy-three patients qualified for the study, 49 of whom completed a postoperative telephone interview. Of the interviewees, 83% did not use or desire an opioid and reported pain <4/10 after discharge. Five patients used an opioid upon discharge, and the average MME consumed was 23 (equivalent to 3 pills of 5 mg oxycodone). No zero-opioid patients had unanticipated follow-up for pain concerns.

CONCLUSIONS

After hospital discharge following laparoscopic appendectomy, most patients have adequate analgesia without opioids. Opioid prescriptions should be offered sparingly and for no more than 25 MME.

LEVEL OF EVIDENCE

Level II.

TYPE OF STUDY

Prognosis study.