Accuracy of MRI in Assessment of High-Grade Partial Distal Biceps Tears.

BACKGROUND: Magnetic resonance imaging (MRI) is commonly used to diagnose and assess the extent of partial distal biceps injuries. The aim of this study was to report on the accuracy of MRI and the effect of injury history and study timing on its performance. METHODS: A retrospective review of all patients who underwent surgical treatment of partial thickness distal biceps tears at a single center by multiple surgeons was performed. Inclusion criteria consisted of the performance of a preoperative MRI and documentation of the intraoperatively visualized extent of the tear, and 68 patients met the criteria for inclusion. A chart review was completed to evaluate the symptom duration, injury history, and tear extent. RESULTS: All patients had distal biceps tears of greater than 50% intraoperatively. However, MRI did not indicate any tearing in 20 (29%) patients, and its sensitivity for high-grade tear was 44%. Magnetic resonance imaging was significantly less likely to be read as high-grade tears in patients with insidious onset of their symptoms in comparison with patients who reported a traumatic onset (27% vs 55%, P = .024). However, the time from symptom onset to MRI did not significantly correlate with diagnosis of a high-grade tear on MRI (r = -0.15, P = .21). CONCLUSIONS: These results indicate that MRI can underreport partial distal biceps tear extent, and this more commonly occurs in patients with insidious onset of pain.

Occult Amyloid Deposition in Older Patients Presenting With Bilateral Carpal Tunnel Syndrome or Multiple Trigger Digits.

PURPOSE: The diagnosis of amyloidosis is important for early intervention, disease monitoring, and prevention of complications and progression. Carpal tunnel syndrome (CTS) and trigger digit (TD) are two common conditions associated with early disease. The purpose of this study was to define disease prevalence among patients with bilateral CTS and multiple TDs and assess for an increased rate of diagnosis in the presence of both. METHODS: Men older than 50 years and women older than 60 years of age diagnosed with bilateral CTS, multiple TDs, or a combination of the 2 were prospectively enrolled in our study. Tenosynovial biopsy samples taken at the time of surgery were tested for the presence of amyloid using Congo red staining. Demographic and medical covariates were also collected and analyzed for differences between amyloid-positive and -negative patients. RESULTS: Fifty-six patients were enrolled in the study, and nine patients tested positive for amyloid deposition. The demographics and medical comorbidities were similar between amyloid-positive and -negative patients. Thirty patients with bilateral CTS were enrolled, and four tested positive for amyloid. For patients with multiple TDs, a total of 17 patients were enrolled, and 4 tested positive for amyloid. Among patients with multiple TDs, only men tested positive for amyloid and were, on average, younger than those who tested negative (61 and 73 years, respectively). Patients presenting with a combination of CTS and TD did not exhibit increased amyloid discovery. CONCLUSIONS: Hand surgeons should consider tenosynovial biopsy in men older than 50 years and women older than 60 years presenting with either bilateral CTS or multiple TDs. TYPE OF STUDY/LEVEL OF EVIDENCE: Prognostic IV.

Application of Tendon With Z-Lengthening Technique.

Tendon deficiency limits repair and reconstructive options after tendon and nerve injuries of the upper extremity. Current treatment options include intercalary tendon autograft, tendon transfers, and two-stage tenodesis, with sacrifice of the flexor digitorum superficialis. These reconstructive techniques are associated with donor site morbidity and limited in the setting of multiple tendon deficiencies. The tendon with z-lengthening (TWZL) technique is presented here as an alternative treatment method for tendon injuries and tendon transfer reconstruction after nerve injuries. The TWZL technique involves splitting a tendon longitudinally, reflecting the freed tendon limb distally, and suture augmentation at the bridge site located at the distal end of the native tendon. The TWZL technique has applications throughout the upper extremity-flexor and extensor tendons injuries, biceps and triceps tendon injuries, and tendon transfers for restoration of hand function after nerve injuries. An illustrative case example is also provided. The experienced hand surgeon should consider the TWZL technique as a potential treatment option when faced with difficult clinical conditions of the hand and upper extremities.

A Systematic Review and Meta-Analysis of Nerve Gap Repair: Comparative Effectiveness of Allografts, Autografts, and Conduits.

BACKGROUND: Ideal nerve repair involves tensionless direct repair, which may not be possible after resection. Bridging materials include nerve autograft, allograft, or conduit. This study aimed to perform a systematic literature review and meta-analysis to compare the meaningful recovery (MR) rates and postoperative complications following autograft, allograft, and conduit repairs in nerve gaps greater than 5 mm and less than 70 mm. A secondary aim was to perform a comparison of procedure costs. METHODS: The search was conducted in MEDLINE from January of 1980 to March of 2020, following Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Studies were included whether they reported nerve injury type, repair type, gap length, and outcomes for MR rates. Thirty-five studies with 1559 nerve repairs were identified. RESULTS: Overall MR for sensory and motor function was not significantly different between autograft ( n = 670) and allograft ( n = 711) across both short and long gaps. However, MR rates for autograft (81.6%) and allograft (87.1%) repairs were significantly higher compared with conduits (62.2%) ( P < 0.05) in sensory short gap repairs. Complication rates were comparable for autograft and allograft but higher for conduit with regard to pain. Analysis of costs showed that total costs for allograft repair were less than autograft in the inpatient setting and were comparable in the outpatient setting. CONCLUSIONS: Literature showed comparable rates of MR between autograft and allograft, regardless of gap length or nerve type. Furthermore, the rates of MR were lower in conduit repairs. In addition, the economic analysis performed demonstrates that allograft does not represent an increased economic burden compared with autograft.

Primary Repair of Chronic Distal Biceps Tendon Tears.

BACKGROUND: This study reports the clinical results following primary repair of distal biceps tendon ruptures more 6 weeks after injury. METHODS: A retrospective review of distal biceps tendon repairs performed by 8 different hand surgeons from January 1, 2015 to October 15, 2020 was performed. Patients with complete tears surgically treated ≥6 weeks after injury without tendon graft were included. Thirty patients qualified and underwent chart review for complication and range of motion (ROM) data. They were contacted for final patient-reported outcome measures (PROMs) using Quick Disabilities of the Arm, Shoulder, and Hand (QuickDASH) and Patient Reported Elbow Evaluation (PREE) scores. Final PROMs were obtained from 21 patients with an average follow-up of 31.3 months (range: 4-71 months). RESULTS: Average time from injury to repair was 71 days (range: 42-204). The average QuickDASH score was 6.6 (±6.2) and PREE score was 7.8 (±8.0). The amount of elbow flexion necessary to complete the repair was documented in 21 patients and averaged 64º (±10º). Postoperatively, patients achieved an average extension/flexion of 1º (±1º) to 138º (±2º) and pronation/supination of 76º (±4º) to 77º (±3º). Complications were reported in 14 patients (47%) and included 2 re-ruptures, 1 adhesive scar formation, 1 superficial infection, 1 intraoperative lateral antebrachial cutaneous nerve laceration, 12 neuropraxias, and 1 case of heterotopic ossification (HO). CONCLUSIONS: Primary repair of chronic distal biceps tendon tears greater than 6 weeks from injury demonstrated excellent PROMs and elbow ROM. However, the complication rate may be higher than early repair.

Evidence-Based Approach to Timing of Nerve Surgery: A Review.

ABSTRACT: Events causing acute stress to the health care system, such as the COVID-19 pandemic, place clinical decisions under increased scrutiny. The priority and timing of surgical procedures are critically evaluated under these conditions, yet the optimal timing of procedures is a key consideration in any clinical setting. There is currently no single article consolidating a large body of current evidence on timing of nerve surgery. MEDLINE and EMBASE databases were systematically reviewed for clinical data on nerve repair and reconstruction to define the current understanding of timing and other factors affecting outcomes. Special attention was given to sensory, mixed/motor, nerve compression syndromes, and nerve pain. The data presented in this review may assist surgeons in making sound, evidence-based clinical decisions regarding timing of nerve surgery.

Efficacy of a single, image-guided corticosteroid injection for glenohumeral arthritis.

BACKGROUND: Limited data are available on the efficacy of cortisone injections for glenohumeral osteoarthritis (GHOA). The amount and longevity of pain relief provided by a single cortisone injection are unclear. Additionally, it remains uncertain how the severity of radiographic GHOA and patient-reported function and pain levels impact the efficacy of an injection. Therefore, we sought to describe the relief provided by a single, image-guided glenohumeral injection in patients with GHOA. We hypothesized that patients with more severe radiographic GHOA and poorer baseline shoulder function would require earlier secondary intervention. METHODS: Patients with symptomatic GHOA who elected to receive a corticosteroid injection for pain relief were prospectively enrolled. A phone interview was conducted to record the baseline Oxford Shoulder Score (OSS) and visual analog scale (VAS) score prior to the injection, as well as the OSS and VAS score at months 1, 2, 3, 4, 6, 9, and 12 after the injection. The endpoint of the study occurred when patients required a second injection, progressed to surgery, or reached month 12. Patients were grouped by their respective baseline OSS (mild vs. moderate or severe) and Samilson-Prieto radiographic classification (mild, moderate, or severe) for analysis. RESULTS: We analyzed 30 shoulders (29 patients). Of the patients, 52% were men. The average age was 66.1 years. No significant difference in overall survival (defined as no additional intervention) was seen between groups based on either the OSS or Samilson-Prieto grade. Additionally, the OSS and VAS score at each follow-up were compared with baseline values. For the entire cohort, a clinically significant difference was seen between baseline and months 1-4 for the OSS and between baseline and months 1-4, 6, 9, and 12 for the VAS score. DISCUSSION: This study aimed to determine the efficacy of corticosteroid injections for GHOA. There were no differences in the need for secondary intervention in this population based on the severity of either the OSS or the Samilson-Prieto radiographic classification. However, patients with more severe shoulder dysfunction based on the OSS did experience statistically significantly greater symptomatic relief than patients with milder dysfunction. Additionally, following a single injection, patients in this cohort experienced statistically and clinically relevant improvements in shoulder function and pain up to 4 months after injection.

Ulnar Abutment Syndrome in the Athlete.

Ulnar abutment (ulnocarpal impaction) syndrome may be a source of ulnar-sided wrist pain in the athlete. This condition results from excessive load transfer across the triangular fibrocartilage complex and ulnocarpal joints with characteristic degenerative changes. It frequently occurs in patients with either static or dynamic ulnar positive variance. Treatment is tailored to the athlete and their sporting demands. Surgical treatment focuses on addressing ulnar variance to unload the ulnocarpal joint, with multiple surgical options, including the metaphyseal closing wedge osteotomy achieving this goal. This review focuses on the presentation, biomechanics, and treatment options for ulnar abutment syndrome in the athlete.

Ulnar-Sided Wrist Pain in the Athlete.

Ulnar-sided wrist pain is a common problem in athletes that can be challenging owing to its frequent combination of overuse in conjunction with acute injury. Repetitive pronosupination, wrist flexion and extension, as well as radial and ulnar deviation can predispose the athlete to injury of ulnar structures. Careful understanding of the sport-specific injuries as well as the underlying biomechanics are key to understanding and treating the athlete. In this article, we discuss the most frequent causes of ulnar-sided wrist pain in the athlete and focus on anatomy and pathophysiology, presentation, and diagnosis, as well as nonoperative and operative treatment options.

Palmar Radiocarpal Artery Vascularized Bone Graft for the Unstable Humpbacked Scaphoid Nonunion With an Avascular Proximal Pole.

PURPOSE: The most challenging scaphoid nonunion is the unstable nonunion with humpbacked collapse coupled with an avascular proximal pole. Dorsal distal radius pedicled vascularized bone grafts (VBGs) are contraindicated in cases of humpback deformity. The free medial femoral condyle VBG is an excellent option but it is an extensive microsurgical procedure with lengthy operative times and dual-limb incisions. In search of a local, volar, vascularized source of bone to treat this challenging subset of scaphoid nonunions, we analyzed our results with a volar distal radius bone graft based on the pedicled palmar radiocarpal artery (PRCA). METHODS: A prospective cohort of 15 unstable nonunions with avascular proximal pole fragments was treated with the PRCA graft and open reduction internal fixation. Preoperative carpal indices revealed a high degree of instability. All 15 lacked punctate bleeding from the proximal pole. All 15 patients were treated with the PRCA VBG technique and scanned with computed tomography at approximately 6 and 12 weeks to assess for interval healing. RESULTS: All nonunions healed with an average cross-sectional trabeculation score of 70% at week 6 and 84% at week 12. Sagittal intrascaphoid angles improved from 50° to 27°, radiolunate angle improved from -20° to -7°, scapholunate angle improved from 86° to 64°, and revised carpal height ratio improved from 1.45 to 1.53, indicating correction of the humpback collapse deformity. Patients were observed an average of 22 months to have no sign of further avascular necrosis. CONCLUSIONS: Pedicled PRCA-VBG successfully addresses the dual needs of the humpbacked scaphoid nonunion with an avascular proximal pole while simultaneously limiting dissection to one limb and avoiding the additional complexities of free tissue transfer. TYPE OF STUDY/LEVEL OF EVIDENCE: Therapeutic II.

Peripheral nerve repair throughout the body with processed nerve allografts: Results from a large multicenter study.

BACKGROUND: Peripheral nerve damage resulting in pain, loss of sensation, or motor function may necessitate a reconstruction with a bridging material. The RANGER® Registry was designed to evaluate outcomes following nerve repair with processed nerve allograft (Avance® Nerve Graft; Axogen; Alachua, FL). Here we report on the results from the largest peripheral nerve registry to-date. METHODS: This multicenter IRB-approved registry study collected data from patients repaired with processed nerve allograft (PNA). Sites followed their own standard of care for patient treatment and follow-up. Data were assessed for meaningful recovery, defined as ≥S3/M3 to remain consistent with previously published results, and comparisons were made to reference literature. RESULTS: The study included 385 subjects and 624 nerve repairs. Overall, 82% meaningful recovery (MR) was achieved across sensory, mixed, and motor nerve repairs up to gaps of 70 mm. No related adverse events were reported. There were no significant differences in MR across the nerve type, age, time-to-repair, and smoking status subgroups in the upper extremity (p > .05). Significant differences were noted by the mechanism of injury subgroups between complex injures (74%) as compared to lacerations (85%) or neuroma resections (94%) (p = .03) and by gap length between the <15 mm and 50-70 mm gap subgroups, 91 and 69% MR, respectively (p = .01). Results were comparable to historical literature for nerve autograft and exceed that of conduit. CONCLUSIONS: These findings provide clinical evidence to support the continued use of PNA up to 70 mm in sensory, mixed and motor nerve repair throughout the body and across a broad patient population.

Testing of Direct Neurorrhaphy Strain.

PURPOSE: To investigate the ideal suture material to test strain at nerve repair sites. Based on nerve strain tolerance, we aimed to determine which suture reliably failed by an average of 5% and a maximum of 8% strain when loaded to failure. METHODS: The median nerve of 19 cadavers was exposed in the distal forearm, transected proximally, and attached to a spring gauge. It was marked 5 cm on either side of its midpoint to measure strain. A laceration was created at its midpoint. We performed a tension-free end-to-end repair with a single epineural suture. Load to failure of the repair site was recorded. We recorded strain at failure and mode of failure (pullout vs breakage). Eight different sutures were tested: 6-0, 8-0, 9-0, and 10-0 nylon; and 6-0, 7-0, 8-0, and 10-0 polypropylene. RESULTS: Average strain at failure of 9-0 nylon most closely approximated 5% (4.9%). Moreover, 8-0 polypropylene and 10-0 nylon and polypropylene failed with average strains less than 5% and a maximum strain of failure less than 8%. Regardless of type, 6-0 to 8-0 caliber suture failed primarily by pullout of the suture from the epineurium whereas 9-0 and 10-0 nylon and polypropylene failed by suture breakage. Decreased precision through increased variability was seen when testing sutures failing via pullout. CONCLUSIONS: Nylon suture size 8-0 has been advocated as the suggested intraoperative aid to test strain at nerve repair sites. Our study suggests that 9-0 nylon may be a more appropriate testing suture because of its more predictable failure via breakage and its failure by a threshold of 5% to 8% strain. Although 8-0 nylon and polypropylene may also represent reasonable testing sutures, 8-0 nylon failed on average above 5% strain, with strains exceeding 8%, and both failed via the mechanism of pullout. CLINICAL RELEVANCE: This study's findings provide information for surgeons attempting to decide during surgery whether to perform direct nerve repair.

Surgical Treatment of Cubital Tunnel in Pediatric Athletes.

Background Cubital tunnel syndrome is the second most common upper extremity peripheral nerve entrapment syndrome. In particular, cubital tunnel has been documented occasionally in young, throwing athletes. Materials and Methods Billing databases were searched for patients undergoing surgical decompression of the ulnar nerve at the elbow, who were age 18 or younger at the time of surgery. Charts were reviewed and patients were included if they had an isolated mononeuropathy consistent with cubital tunnel syndrome and were symptomatic. Data on age of onset, duration of symptoms, Dellon classification, nerve subluxation, provocative testing results, nerve conductions, and exacerbating activities were abstracted. Patients were contacted for a postsurgical follow-up questionnaire. Results Seven patients were identified. The average age was 16, and duration of symptoms was 7 months. All seven patients had normal electrodiagnostic studies and had failed a course of conservative treatment. All were satisfied with surgery and felt improvement. One stopped playing their sport, and three had mild symptoms with varied activities. Conclusion Although uncommon, pediatric cubital tunnel syndrome does occur. Surgical release improves symptoms and return to activities. Nevertheless, some degree of symptoms often persists. Electrodiagnostic studies may be negative in many patients with an otherwise consistent history and examination. Level of Evidence This is a level IV therapeutic study.

Establishing the appropriate position of proximal humerus locking plates: a cadaveric study of five plating systems and their anatomic reference measurements.

BACKGROUND: The present study aimed to determine anatomic references for the placement of five proximal humerus locking plates. METHODS: Five proximal humerus locking-plate systems were placed on six human shoulder cadavers. Plates were positioned by fluoroscopic confirmation so that the inferior oblique screw was within 5 mm of the inferomedial cortex. Plate position was measured using the superior border of the pectoralis major tendon (PMT) to the bottom of the first slotted or nonlocking hole and top of the plate to the top of the greater tuberosity. The distance from the PMT insertion to the top of the humeral head was measured as a control. RESULTS: There was consistency within each plating system for both the distance from the PMT insertion to the first hole and the top of the plate to the greater tuberosity: Synthes first-generation [mean (SD) 13.7 mm (3.1 mm); 10 mm (1.3) mm], Synthes second-generation [28.2 mm (2.2 mm); 18.5 mm (2.7 mm)], Biomet OptiLock® [25.5 mm (2.7 mm); 18.7 mm (2 mm)], Stryker AxSOS® [5 mm (2.8 mm); 12.3 mm (3.3 mm)] and Acumed Polarus® [9.5 mm (1.8 mm); 14.8 mm (1.6 mm)]. CONCLUSIONS: The present study provides measurements that improve the accuracy of plate positioning for five plating systems.

Complications of Distal Biceps Repair.

Modern techniques to repair the distal biceps tendon include one-incision and 2-incision techniques that use transosseous sutures, suture anchors, interference screws, and/or cortical buttons to achieve a strong repair of the distal biceps brachii. Repair using these techniques has led to improved functional outcomes when compared with nonoperative treatment. Most complications consist of neuropraxic injuries to the lateral antebrachial cutaneous nerve, posterior interosseous nerve, stiffness and weakness with forearm rotation, heterotopic ossification, and wound infections. Although complications certainly affect outcomes, patients with distal biceps repairs report a high satisfaction rate after repair.

Outcomes of short-gap sensory nerve injuries reconstructed with processed nerve allografts from a multicenter registry study.

BACKGROUND: Short-gap digital nerve injuries are a common surgical problem, but the optimal treatment modality is unknown. A multicenter database was queried and analyzed to determine the outcomes of nerve gap reconstructions between 5 and 15 mm with processed nerve allograft. METHODS: The current RANGER registry is designed to continuously monitor and compile injury, repair, safety, and outcomes data. Centers followed their own standard of care for treatment and follow-up. The database was queried for digital nerve injuries with a gap between 5 and 15 mm reporting sufficient follow-up data to complete outcomes analysis. Available quantitative outcome measures were reviewed and reported. Meaningful recovery was defined by the Medical Research Council Classification (MRCC) scale at S3-S4 for sensory function. RESULTS: Sufficient follow-up data were available for 24 subjects (37 repairs) in the prescribed gap range. Mean age was 43 years (range, 23-81). Mean gap was 11 ± 3 (5-15) mm. Time to repair was 13 ± 42 (0-215) days. There were 25 lacerations, 8 avulsion/amputations, 2 gunshots, 1 crush injury, and 1 injury of unknown mechanism. Meaningful recovery, defined as S3-S4 on the MRCC scales, was reported in 92% of repairs. Sensory recovery of S3+ or S4 was observed in 84% of repairs. Static 2PD was 7.1 ± 2.9 mm (n = 19). Return to light touch was observed in 23 out of 32 repairs reporting Semmes-Weinstein monofilament outcomes (SWMF). There were no reported nerve adverse events. CONCLUSION: Sensory outcomes for processed nerve allografts were equivalent to historical controls for nerve autograft and exceed those of conduit. Processed nerve allografts provide an effective solution for short-gap digital nerve reconstructions.

Decreases in theta and increases in high frequency activity underlie associative memory encoding.

Episodic memory encoding refers to the cognitive process by which items and their associated contexts are stored in memory. To investigate changes directly attributed to the formation of explicit associations, we examined oscillatory power captured through intracranial electroencephalography (iEEG) as 27 neurosurgical patients receiving subdural and depth electrodes for seizure monitoring participated in a paired associates memory task. We examined low (3-8Hz) and high (45-95Hz) frequency activity, and found that the successful formation of new associations was accompanied by broad decreases in low frequency activity and a posterior to anterior progression of increases in high frequency activity in the left hemisphere. These data suggest that the observed patterns of activity may reflect the neural mechanisms underlying the formation of novel item-item associations.

Ulnar-sided wrist pain in the athlete.

The athlete's wrist, especially those using bats, sticks, racquets, or clubs, is subjected to extremely high torque loads during athletic activities. These loads stress the stabilizing elements of the ulnocarpal and distal radioulnar complexes. Lesions of these regions can lead to painful dysfunction and instabilities that negatively impact athletic performance. This article reviews some of the common ulnar-sided maladies focusing on anatomy, biomechanics, diagnosis, and treatment.

Radiographic evaluation of the elbow.

Despite a number of advanced imaging modalities, plain film x-ray is essential for diagnostic evaluation of the elbow. Although computed tomography and magnetic resonance imaging continue to provide many uses in subtle processes or advanced evaluation, x-rays should typically provide initial, and often all, necessary imaging. Plain film imaging is used to evaluate trauma including fractures and dislocations, occult or suspected bony injury, instability patterns, tumor, arthritis and degenerative disease, and causes of associated pathology such as compression neuropathy.

Computer-assisted navigation for dorsal percutaneous scaphoid screw placement: a cadaveric study.

PURPOSE: To investigate computer-assisted surgery (CAS) for dorsal insertion of percutaneous scaphoid screws and to compare operative time, accuracy, and fluoroscopy time with the traditional mini C-arm method. We hypothesized that CAS techniques would improve accuracy, reduce actual K-wire insertion time, and decrease fluoroscopy time. METHODS: Ten fresh cadaveric upper limbs were randomized to either CAS or traditional dorsal percutaneous scaphoid screw placement by a single surgeon. Custom orthoses were applied to the CAS arms followed by intraoperative computed tomography (CT) scan and navigation calibration. Time was recorded for the portion of setup that required surgeon input, ideal guide wire placement, and fluoroscopy. Postoperative CT scans of the CAS arms were obtained to confirm accuracy. Two-tailed unpaired Student t test was used to analyze the outcome variables. RESULTS: The CAS group required on average 4.8 ± 0.8 minutes longer for setup. The time for placement of the guidewire in the ideal position was 4.6 ± 1.5 minutes in the CAS group compared with 11.8 ± 4.4 minutes in the control group. Fluoroscopy time was 18 ± 4 seconds for the CAS group and 114 ± 38 seconds for the control group. Postoperative CT scans demonstrated 1.5 ± 0.6 mm maximum deviation from the planned ideal screw. No significant differences were found in the accuracy between methods, the number of guidewire attempts, or the total surgical time. CONCLUSIONS: Computer-assisted surgery navigation of dorsal percutaneous scaphoid screw placement takes on average 5 minutes longer to set up, but leads to significantly reduced guidewire placement time and no differences in overall procedural time. This CAS method was as accurate as the traditional method and resulted in an approximate 6-fold reduction in fluoroscopy time. CLINICAL RELEVANCE: This is an effective imaging alternative to the mini C-arm for scaphoid fixation using existing intraoperative CT scanners and navigation software.