What Factors Are Associated With Early Career Attrition Among Orthopaedic Surgeons in the United States?

BACKGROUND: The attrition of medical personnel in the United States healthcare system has been an ongoing concern among physicians and policymakers alike. Prior studies have shown that reasons for leaving clinical practice vary widely and may range from professional dissatisfaction or disability to the pursuit of alternative career opportunities. Whereas attrition among older personnel has often been understood as a natural phenomenon, attrition among early-career surgeons may pose a host of additional challenges from an individual and societal perspective. QUESTIONS/PURPOSES: (1) What percentage of orthopaedic surgeons experience early-career attrition, defined as leaving active clinical practice within the first 10 years after completion of training? (2) What are the surgeon and practice characteristics associated with early-career attrition? METHODS: In this retrospective analysis drawn from a large database, we used the 2014 Physician Compare National Downloadable File (PC-NDF), a registry of all healthcare professionals in the United States participating in Medicare. A total of 18,107 orthopaedic surgeons were identified, 4853 of whom were within the first 10 years of training completion. The PC-NDF registry was chosen because it has a high degree of granularity, national representativeness, independent validation through the Medicare claims adjudication and enrollment process, and the ability to longitudinally monitor the entry and exit of surgeons from active clinical practice. The primary outcome of early-career attrition was defined by three conditions, all of which had to be simultaneously satisfied ("condition one" AND "condition two" AND "condition three"). The first condition was presence in the Q1 2014 PC-NDF dataset and absence from the same dataset the following year (Q1 2015 PC-NDF). The second condition was consistent absence from the PC-NDF dataset for the following 6 years (Q1 2016, Q1 2017, Q1 2018, Q1 2019, Q1 2020, and Q1 2021), and the third condition was absence from the Centers for Medicare and Medicaid Services Opt-Out registry, which tracks clinicians who have formally discontinued enrollment in the Medicare program. Of the 18,107 orthopaedic surgeons identified in the dataset, 5% (938) were women, 33% (6045) were subspecialty-trained, 77% (13,949) practiced in groups of 10 or more, 24% (4405) practiced in the Midwest, 87% (15,816) practiced in urban areas, and 22% (3887) practiced at academic centers. Surgeons not enrolled in the Medicare program are not represented in this study cohort. A multivariable logistic regression model with adjusted odds ratios and 95% confidence intervals was constructed to investigate characteristics associated with early-career attrition. RESULTS: Among the 4853 early-career orthopaedic surgeons identified in the dataset, 2% (78) were determined to experience attrition between the first quarter 2014 and the same point in 2015. After controlling for potential confounding variables such as years since training completion, practice size, and geographic region, we found that women were more likely than men to experience early-career attrition (adjusted OR 2.8 [95% CI 1.5 to 5.0]; p = 0.006]), as were academic orthopaedic surgeons compared with private practitioners (adjusted OR 1.7 [95% CI 1.02 to 3.0]; p = 0.04), while general orthopaedic surgeons were less likely to experience attrition than subspecialists (adjusted OR 0.5 [95% CI 0.3 to 0.8]; p = 0.01). CONCLUSION: A small but important proportion of orthopaedic surgeons leave the specialty during the first 10 years of practice. Factors most-strongly associated with this attrition were academic affiliation, being a woman, and clinical subspecialization. CLINICAL RELEVANCE: Based on these findings, academic orthopaedic practices might consider expanding the role of routine exit interviews to identify instances in which early-career surgeons face illness, disability, burnout, or any other forms of severe personal hardships. If attrition occurs because of such factors, these individuals could benefit from connection to well-vetted coaching or counseling services. Professional societies might be well positioned to conduct detailed surveys to assess the precise reasons for early attrition and characterize any inequities in workforce retention across a diverse range of demographic subgroups. Future studies should also determine whether orthopaedics is an outlier, or whether 2% attrition is similar to the proportion in the overall medical profession.

Endoscopic Versus Open Carpal Tunnel Release: A Detailed Analysis Using Time-Driven Activity-Based Costing at an Academic Medical Center.

PURPOSE: In order to effectively improve value in health care delivery, providers must thoroughly understand cost drivers. Time-driven activity-based costing (TDABC) is a novel accounting technique that may allow for precise characterization of procedural costs. The purpose of the present study was to use TDABC to characterize costs in a high-volume, low-complexity ambulatory procedure (endoscopic vs open carpal tunnel release [CTR]), identify cost drivers, and inform opportunities for clinical improvement. METHODS: The costs of endoscopic and open CTR were calculated in a matched cohort investigation using TDABC. Detailed process maps including time stamps were created accounting for all clinical and administrative activities for both the endoscopic and the open treatment pathways on the day of ambulatory surgery. Personnel cost rates were calculated accounting for capacity, salary, and fringe benefits. Costs for direct consumable supplies were based on purchase price. Total costs were calculated by aggregating individual resource utilization and time data and were compared between the 2 surgical techniques. RESULTS: Total procedural cost for the endoscopic CTR was 43.9% greater than the open technique ($2,759.70 vs $1,918.06). This cost difference was primarily driven by the disposable endoscopic blade assembly ($217), direct operating room costs related to procedural duration (44.8 vs 40.5 minutes), and physician labor. CONCLUSIONS: Endoscopic CTR is 44% more expensive than open CTR compared with a TDABC methodology at an academic medical center employing resident trainees. Granular cost data may be particularly valuable when comparing these 2 procedures, given the clinical equipoise of the surgical techniques. The identification of specific cost drivers with TDABC allows for targeted interventions to optimize value delivery. TYPE OF STUDY/LEVEL OF EVIDENCE: Economic Analysis II.

Use of an Automated Mobile Phone Messaging Robot in Postoperative Patient Monitoring.

BACKGROUND: Mobile phone messaging software robots allow clinicians and healthcare systems to communicate with patients without the need for human intervention. The purpose of this study was to (1) describe a method for communicating with patients postoperatively outside of the traditional healthcare setting by utilizing an automated software and mobile phone messaging platform and to (2) evaluate the first week of postoperative pain and opioid use after common ambulatory hand surgery procedures. MATERIALS AND METHODS: The investigation was a prospective, multicenter investigation of patient-reported pain and opioid usage after ambulatory hand surgery. Inclusion criteria included any adult with a mobile phone capable of text messaging, who was undergoing a common ambulatory hand surgical procedure at one of three tertiary care institutions. Participants received daily, automated text messages inquiring about their pain level and how many tablets of prescription pain medication they had taken in the past 24 h. Initial 1-week response rate was assessed and compared between different patient demographics. Patient-reported pain and opioid use were also quantified for the first postoperative week. Statistical significance was set as p < 0.05. RESULTS: Forty-seven (n = 47) patients were enrolled in this investigation. Total response rate of both pain and opioid medication questions through 7 days was 88.3%. Pain trended down on a daily basis for the first postoperative week, with the highest levels of pain being reported in the first 48 h after surgery. Patients reported an average use of 15.9 ± 14.8 tablets of prescription opioid pain medication. CONCLUSIONS: We find that a mobile phone messaging software robot allows for effective data collection of postoperative pain and pain medication use. Patients undergoing common ambulatory hand procedures utilized an average of 16 tablets of opioid medication in the first postoperative week.

A Novel Prescription Method Reduces Postoperative Opioid Distribution and Consumption: A Randomized Clinical Trial.

BACKGROUND: Prescription opioid abuse in the United States has risen substantially over the past 2 decades. Narcotic prescription refill restrictions may paradoxically be contributing to this epidemic. We investigated a novel, refill-based opioid prescription method to determine whether it would alter postoperative narcotic distribution or consumption. METHODS: In this randomized controlled trial, patients undergoing internal fixation of distal radius fractures or thumb carpometacarpal joint arthroplasty received either a single prescription for all postoperative narcotics (control arm) or the same amount of pain medication divided into 3 equal prescriptions to be filled as needed (experimental arm). Outcomes included total narcotics dispensed, measured in morphine milligram equivalents (MME) through a prescription monitoring program, patient-reported opioid consumption versus opioid not consumed, and a satisfaction survey. RESULTS: Forty-eight participants were enrolled; 25 were randomized to the control arm and 23 to the experimental arm. At 8 weeks post-op, fewer opioids had been dispensed to the experimental arm (177 ± 94 vs 287 ± 123 MME, P = .0025). At 6-week follow-up, the experimental arm reported lower narcotic consumption (124 ± 105 vs 214 ± 110 MME, P = .0131). Subanalysis of the independent surgeries yielded similar results. Some patients reported insurance issues when filling subsequent prescriptions. Consequently, although 100% of control arm patients reported good pain control, only 82.6% of experimental arm patients said likewise (P = .0455). CONCLUSIONS: This randomized clinical trial demonstrated that patients obtained and consumed fewer narcotics when postoperative opioids were given in a refill-based prescription method. More research is needed to determine whether this opioid distribution method is reproducible, translatable, and feasible.

Glass Ceiling in Hand Surgery: Publication Trends by Gender.

Background: Women are frequently underrepresented across surgical subspecialties and may face barriers to academic advancement. Abstracts presented at American Society for Surgery of the Hand annual meeting (ASSH-AM) highlight some of the top research in hand surgery. We sought to explore differences in abstract characteristics and publication rates based on senior author gender.Though there have been increasing efforts at inclusivity in orthopedic and plastic surgery, women face several barriers to entering the field, publish less frequently, and are underrepresented in leadership positions. Understanding the stages at which discrepancies in research productivity exist may help to address these challenges. Methods: Abstracts from the 2010-2017 ASSH-AMs were reviewed to determine basic characteristics. Author gender was determined through both a search of institutional websites for gender-specific pronouns and inference of gender based on first name. Subsequent full manuscript publications corresponding to the abstracts were identified through a systematic search of PubMed and Google Scholar. Results: A total of 560/620 (90.3%) abstracts from 2010-2017 had an identifiable senior author gender (14.5% female). No differences were noted between male- and female-authored abstracts regarding study design including sample size or level of evidence. Female senior authors were more likely than males to author abstracts focused on pediatrics (19.8% vs 9.4%, p=0.01) and were more likely to collaborate with female first authors (41.3% vs 20.0%, p<0.01). Abstract publication rates were lower for female senior authors versus male senior authors (61.7% vs 74.5%, p=0.02). Conclusion: The number of abstracts with female senior authors had similar representation to the membership proportion of women in the ASSH. There were few differences in abstract characteristics based on senior author gender, though senior authors tend to collaborate with investigators of the same gender. Abstracts authored by females were published 13% less frequently overall, meriting further exploration. Level of Evidence: III.

Orthopedic Surgery Residency Application Process in 2020 - Has Diversity been Affected?

Background: Orthopedic surgery is currently the least diverse field in medicine. COVID-19 necessitated a virtual rotation and interview process for orthopedic residency applications in 2020. Given the pressing need to address disparities within the field, any change in the application process should be examined with regard to the potential effects it could have on the diversity of trainees in orthopedic surgery. The purpose of this study was to evaluate the effect of virtual rotations and interviews on the demographic distribution of applicants to orthopedic surgery residency. Methods: A retrospective review of orthopedic surgery residency applicants was performed comparing the 2018 and 2020 application cycle. Self-reported ethnicity on Electronic Residency Application Service (ERAS) forms was recorded for all applicants who met prescreening criteria, were invited to interview and who completed interviews. The proportion of underrepresented minority (URM) applicants was compared between these two cohorts. Results: There were no significant differences between the 2018 and 2020 application cohorts in terms of number or proportion of URM applicants that met initial screening criteria (p=0.7598), female applicants that met initial screening criteria (p=0.3106), URM applicants who were invited to interview (p=0.6647), or female applicants who were invited to interview (p=0.63). Overall, applicants in the 2018 cycle were 2.38 times more likely to be invited to interview (OR 2.38, 95% CI 1.6886-3.3623, p<0.0001) and applicants who were invited to interview were 20.96 times more likely to interview in the 2020 cycle than in the 2018 cycle (OR 20.96, 95% CI 4.89-90.09, p<0.0001). Conclusion: The proportion of URMs applying to orthopedic surgery residency was not significantly different after transitioning to a virtual rotation and interview platform at the single institution studied. Applicants were 2.38 times more likely to be invited to interview in 2018 and were 20.96 times more likely to attend the interview in 2020.Level of Evidence: III.

Does Removing the Photograph and Name Change the Reviewer's Perception of Orthopaedic Residency Applicants?

INTRODUCTION: Orthopaedic surgery remains the least diverse field in medicine regarding female and minority representation. Scarce literature exists evaluating the role of implicit bias in the residency application process. We hypothesized that applicants perceived as underrepresented minorities in orthopaedic surgery (URMs) based on their photograph or name would have a decreased likelihood of being invited to interview. METHODS: Data from the 2018 to 2019 orthopaedic residency application cycle were collected from a single institution. Applications were classified URM or non-URM. After the application cycle was completed, the URM applications were propensity matched with non-URM applicants. Photographs and names were removed, and the applications were rereviewed by the Residency Applicant Review committee. Rank-in-group and the likelihood of being invited for an interview were compared. RESULTS: Four hundred eleven applications were included with 27.5% URM and 72.5% non-URM. During the regular application cycle, 34.7% of those invited to interview were URM and 50% of those who were ranked-to-match range were URM. After propensity matching, 90 matched pairs were rereviewed with their photograph and name removed. In the regular application cycle, the URM applicant was 3.8 times more likely to get an interview than the matched non-URM applicant (odds ratio, 3.8, 95% confidence interval, 1.7 to 8.8, P = 0.0014). In the "blinded" condition, the URM candidate was 2.5 times more likely to get an interview than the non-URM candidate (odds ratio, 2.5, 95% confidence interval, 1.1 to 6.2 P = 0.034). In the unblinded condition, the URM candidate had a higher ranking within their group than the corresponding non-URM applicant (P = 0.0005). DISCUSSION: Contrary to our initial hypothesis, URM applicants were invited to interview at a higher rate than non-URM applicants, both in the regular application cycle and in the propensity-matched "blinded" condition. This suggests that implicit bias based on the picture or name is not negatively affecting URM students during the application review process at our institution. LEVEL OF EVIDENCE: 3.

Safety and Efficacy of Forearm Tourniquet Compared to Upper Arm Tourniquet for Local Intravenous Regional Anesthesia in Hand Surgery: A Randomized Clinical Trial.

BACKGROUND: Forearm tourniquets may offer decreased doses of anesthetic, shorter procedure times, and less pain compared to upper arm tourniquets. There is limited data comparing the clinical efficacy of forearm Bier blocks to conventional upper arm Bier blocks. The purpose of this study was to assess the effectiveness, complications, duration, cost, and patient satisfaction between forearm and upper arm Bier blocks during surgery. METHODS: Sixty-six carpal tunnel release, ganglion excision, or trigger finger procedures were performed. Patients were randomized to 3 groups: upper arm tourniquet for 25 minutes, forearm tourniquet for 25 minutes, or forearm tourniquet with immediate deflation following the procedure (<25 minutes). The efficacy of surgical anesthesia, tourniquet discomfort, and supplementary local anesthetic administration were recorded. Pain was assessed intraoperatively and postoperatively. Patient satisfaction was assessed on the first postoperative day. RESULTS: No difference was observed between groups with respect to pain, satisfaction, or administration of supplemental medication. The tourniquet time for the group with immediate deflation following procedure was shorter by an average of 9.3 minutes. Total hospital charges were 9.95% cheaper with immediate tourniquet deflation compared to procedures where the tourniquet remained inflated for at least 25 minutes. CONCLUSION: The forearm Bier block is a safe, efficient, cost-effective technique for intravenous regional anesthesia during hand surgery, and tourniquet deflation immediately following the procedure (<25 minutes) does not increase incidence of complications. The forearm tourniquet reduces the dose of local anesthetic and therefore risk for systemic toxicity, with similar effectiveness as compared to the upper arm technique.Level of Evidence: II.

Postoperative care via smartphone following carpal tunnel release.

INTRODUCTION: This study explores a novel smartphone application for postoperative care following carpal tunnel release (CTR). We hypothesized that a software-based 'virtual visit' for CTR could be safe, effective and convenient for the patient. METHODS: Our group developed the software application utilized in this study. Interactive steps with video instructions enabled patients to complete dressing and suture removal, capture a wound photo, answer a question about median nerve symptoms and capture a video of finger range of motion. Adult patients undergoing endoscopic or open CTR were enrolled. Prior to their scheduled postoperative visit, patients received and completed the module using their smartphone. Agreement between findings of the virtual visit and the corresponding in-person clinical visit was assessed using kappa values. RESULTS: Twenty-two patients were contacted regarding study enrolment and 17 patients were enrolled (ages 23-63, mean 48.2, 6M, 11F). Of 16 patients who participated, all completed dressing removal. Ten of 16 patients removed their sutures successfully. Fourteen patients captured a clinically adequate wound photo and 15 patients answered a question about median nerve symptoms. Fourteen patients captured a range of motion video. Software assessments of surgical wounds, nerve symptoms and physical exams agreed strongly with clinical assessments. DISCUSSION: Most patients were able to respond to a question about their symptoms, provide clinical assessment of their wound via a photo and record a video of their range of motion. Suture removal was the most difficult task. More investigation is needed to determine which patients can reliably remove their sutures.

Intraoperative Point of View Video Capture and Surgical Segmentation in Carpal Tunnel Release: A Feasibility Analysis.

OBJECTIVE: The purpose of this study was to (1) examine the feasibility of intraoperative point of view video while performing open and endoscopic carpal tunnel release (CTR), (2) define surgical segments of CTR, and (3) describe the duration of various surgical steps of open versus endoscopic CTR in a teaching setting. DESIGN: Fellowship trained hand surgeons reached consensus on surgical segments for CTR. Adult patients 18 and older previously indicated for CTR in clinic were eligible. Head-mounted point-of-view cameras were worn during endoscopic and open CTR by resident surgeons. Video was reviewed to determine segment duration. Independent sample t tests were used for comparison of duration by technique with statistical significance set as p < 0.05. SETTING: University of Iowa Hospitals and Clinics; 200 Hawkins Dr, Iowa City, IA 52242; Tertiary Academic Medical Center. PARTICIPANTS: Orthopedic Surgery Residents and Orthopedic Surgery Faculty. RESULTS: Surgical segments were defined as incision, dissection of superficial soft tissue structures, transection of the carpal ligament, and surgical incision closure. Twelve of 14 video capture events yielded data. In the teaching setting, the average duration of endoscopic CTR was 609.5 seconds (±111.07) versus 547.75 seconds (±82.06) for open with p value = 0.406. No surgical segments were significantly different. Transition time from dissection to ligament transection differed significantly (p = 0.004) between endoscopic (46.88 seconds ± 19.19) and open (9.0 seconds ± 7.90) CTR. Transition time between ligament transection and closure was significantly different (p = 0.029) among endoscopic (50.5 seconds ± 15.0) and open (26.25 seconds ± 2.99) CTR. CONCLUSIONS: Point-of-view video capture is feasible for the capture of video during a common hand surgery procedure. A method for managing device battery power is necessary for future applications. CTR can be defined as, and described in, individual procedure segments potentially useful for surgical education as well as efficiency improvements. Identification of surgical segments may aid the development of better objective tools for the assessment of surgeon skill and competency for common orthopedic procedures.

Delivery of Patient-Reported Outcome Instruments by Automated Mobile Phone Text Messaging.

BACKGROUND: Patient-reported outcome (PRO) instruments allow patients to interpret their health and are integral in evaluating orthopedic treatments and outcomes. The purpose of this study was to define: (1) correlation between PROs collected by automated delivery of text messages on mobile phones compared with paper delivery; and (2) patient use characteristics of a technology platform utilizing automated delivery of text messages on mobile phones. METHODS: Paper versions of the 12-Item Short Form Health Survey (SF-12) and the short form of the Disabilities of the Arm, Shoulder and Hand (QuickDASH) were completed by patients in orthopedic hand and upper extremity clinics. Over the next 48 hours, the same patients also completed the mobile phone portion of the study outside of the clinic which included text message delivery of the SF-12 and QuickDASH, assigned in a random order. Correlations between paper and text message delivery of the 2 PROs were assessed. RESULTS: Among 72 patients, the intraclass correlation coefficient (ICC) between the written and mobile phone delivery of QuickDASH was 0.91 (95% confidence interval [CI], 0.85-0.95). The ICC between the paper and mobile phone delivery of the SF-12 physical health composite score was 0.88 (95% CI, 0.79-0.93) and 0.86 (95% CI, 0.75-0.92) for the SF-12 mental health composite score. CONCLUSIONS: We find that text message delivery using mobile phones permits valid assessment of SF-12 and QuickDASH scores. The findings suggest that software-driven automated delivery of text communication to patients via mobile phones may be a valid method to obtain other PRO scores in orthopedic patients.

Distal Radius Hemiarthroplasty.

INTRODUCTION: Due to a higher risk for implant loosening, particularly of the distal component, patients with physically demanding lifestyles are infrequently considered for total wrist arthroplasty (TWA). A distal radius hemiarthroplasty may obviate the need for the strict restrictions recommended for patients treated by TWA, thus providing another surgical option for active patients with severe wrist arthritis, especially those with articular degeneration of the lunate facet of the radius, capitate head, or combination of both, who are not typically candidates for traditional motion-preserving procedures. MATERIALS AND METHODS: Eight fresh-frozen cadaver limbs (age range, 43-82 years) with no history of rheumatoid arthritis or upper extremity trauma were used. Radiodense markers were inserted in the radius and hand. Posteroanterior (PA) fluoroscopic images with the wrist in neutral, radial deviation, and ulnar deviation, and lateral images with the wrist in neutral, flexion, and extension were obtained for each specimen before implantation, after distal radius hemiarthroplasty, and after combined hemiarthroplasty and PRC. RESULTS: On the PA images, the capitate remained within 1.42 and 2.21 mm of its native radial-ulnar position following hemiarthroplasty and hemiarthroplasty with PRC, respectively. Lateral images showed the capitate remained within 1.06 mm of its native dorsal-volar position following hemiarthroplasty and within 4.69 mm following hemiarthroplasty with PRC. Following hemiarthroplasty, capitate alignment changed 2.33 and 2.59 mm compared with its native longitudinal alignment on PA and lateral films, respectively. These changes did not reach statistical significance. As expected, significant shortening in longitudinal alignment was seen on both PA and lateral films for hemiarthroplasty with PRC. CONCLUSION: A distal radius implant hemiarthroplasty with or without a PRC provides good static alignment of the wrist in a cadaver model and thus supports the concept as potential treatment alternatives for advanced wrist arthritis; however, combined hemiarthroplasty with a PRC has more clinical relevance because it avoids the risk of proximal carpal row instability and eliminates the commonly arthritic radioscaphoid joint.

Postsurgical complications following distal radius volar plating in a diabetic population at short-term follow-up.

BACKGROUND: Diabetes mellitus increases the risk of complications following operative treatment of lower extremity fractures. There is little published data establishing the impact of diabetes following surgical treatment of upper extremity fractures. This investigation aimed to compare the incidence of short-term postsurgical complications following volar locked plating of distal radius fractures in patients with and without diabetes. METHODS: A retrospective matched cohort investigation of 33 diabetics matched 1:2 to 66 non-diabetics was performed, accounting for age, gender, fracture type, and smoking status. Electronic medical records and radiographs were reviewed for all major and minor postsurgical complications. Demographic characteristics, postoperative radiographic parameters, and final range of motion were also compared. Mean follow-up was 5.3 ± 8.2 and 5.5 ± 7.8 months for diabetics and non-diabetics, respectively. RESULTS: The diabetic cohort had a significantly higher overall complication rate with 24 postsurgical complications affecting 12 patients (36 %) compared to 16 complications affecting 12 patients (18 %) in the non-diabetic cohort. There was no difference in the incidence of major complications requiring operative intervention. Minor complications were significantly more common in the diabetic group and were largely accounted for by peripheral neuritis with an incidence of 30 %. Final radiographic outcomes and range of motion were similar. CONCLUSIONS: Diabetics experienced a greater incidence of minor postsurgical complications following volar locked plating of distal radius fractures when compared to a matched, control population. The difference in outcomes is largely accounted for by the increased incidence of peripheral neuritis among diabetics. Diabetic patients should be counseled pre-operatively regarding their elevated risk profile.

A case report of bilateral mirror clubfeet and bilateral hand polydactyly.

We report a rare case of a patient with bilateral mirror clubfeet and bilateral hand polydactyly. The patient presented to our orthopaedic clinic with bilateral mirror clubfeet, each with eight toes, and bilateral hands with six fingers and a hypoplastic thumb. The pattern does not fit any described syndrome such as Martin or Laurin-Sandrow syndrome. Treatments by an orthopaedic pediatric surgeon and an orthopaedic pediatric hand surgeon are described. The patient achieved excellent functional and cosmetic outcomes at four year follow-up.

MRI-apparent localized deformation of the median nerve within the carpal tunnel during functional hand loading.

In MR images, the median nerve of carpal tunnel syndrome (CTS) patients frequently appears flatter than in healthy subjects. The purpose of this work was to develop a metric to quantify localized median nerve deformation rather than global nerve flattening, the hypothesis being that localized median nerve deformation would be elevated in CTS patients. Twelve patients with CTS and 12 matched normals underwent MRI scanning in eight isometrically loaded hand conditions. 2D cross sections of the proximal and distal tunnel were analyzed for nerve cross sectional area, flattening ratio, and a position shift to the dorsal side of the tunnel. Additionally, new metrics based on the angulation of the nerve perimeter in 0.5-mm lengths around the boundary were calculated. The localized deformation metrics were able to detect differences between CTS patients and healthy subjects that could not be appreciated from the flattening ratio. During most hand activities, normal subjects had a higher average percentage of locally deformed nerve boundary than did CTS patients, despite having a rounder overall shape. Less local nerve deformation in the CTS patient group resulting from its interaction with flexor tendons suggests that the nerve may be less compliant in CTS patients.

Day-to-day variability of median nerve location within the carpal tunnel.

BACKGROUND: Carpal tunnel syndrome is a commonly encountered entrapment disorder resulting from mechanical insult to the median nerve. Magnetic resonance imaging (MRI)-based investigations have documented typical locations of the median nerve within the carpal tunnel; however, it is unclear whether those locations are consistent within an individual on different days. METHODS: To determine the day-to-day variability of nerve location, 3.0T MRI scans were acquired from six normal volunteers over multiple sessions on three different days. Half of the scans were acquired with the wrist in neutral flexion and the fingers extended, and the other half were acquired with the wrist in 35 degrees of flexion and the fingers flexed. Prior to half of the scans (in both poses), subjects performed a preconditioning routine consisting of specified hand activities and several repetitions of wrist flexion/extension. The shape, orientation, location, and location radius of variability of the median nerve and three selected flexor tendons were determined for each subject and compared between days. FINDINGS: Two of the six subjects had substantial variability in nerve location when the wrist was in neutral, and four of the subjects had high variability in nerve position when the wrist was flexed. Nerve variability was typically larger than tendon variability. The preconditioning routine did not decrease nerve or tendon location variability in either the neutral or the flexed wrist positions. INTERPRETATION: The high mobility and potential for large variability in median nerve location within the carpal tunnel needs to be borne in mind when interpreting MR images of nerve location.

Individual flexor tendon identification within the carpal tunnel: A semi-automated analysis method for serial cross-section MR images.

Carpal tunnel syndrome is commonly viewed as resulting from chronic mechanical insult of the median nerve by adjacent anatomical structures. Both the median nerve and its surrounding soft tissue structures are well visualized on magnetic resonance (MR) images of the wrist and hand. Addressing nerve damage from impingement of flexor digitorum tendons co-occupying the tunnel is attractive, but to date has been restricted by lack of means for making individual identifications of the respective tendons. In this image analysis work, we have developed a region-growing method to positively identify each individual digital flexor tendon within the carpal tunnel by tracking it from a more distal MR section where the respective tendon identities are unambiguous. Illustratively, the new method was applied to MRI scans from four different subjects in a variety of hand poses. Conventional shape measures yielded less discriminatory information than did evaluations of individual tendon location and arrangement. This new method of rapid identification of individual tendons will facilitate analysis of tendon/nerve interactions within the tunnel, thereby providing better information about mechanical insult of the median nerve.