Late-presenting dural leak following spine fusion in the pediatric population

PURPOSE

The purpose is to describe how patients with a late-presenting dural leak (LPDL) after posterior spinal fusion (PSF) was diagnosed and treated at a single institution.

METHODS

Of the 1991 patients who underwent a PSF between 2010 and 2018, 6 patients were identified with a clinical course consistent with a potential LPDL.

RESULTS

Six patients with median age 16.9 years had onset of headache ranging 1-12 weeks postoperatively (median 6.5 weeks). All six patients presented with positional headache, and half (3/6) presented with emesis. 5/6 patients underwent contrast brain MRI, which demonstrated pachymeningeal enhancement. 4/5 patients with dural enhancement went on to have CT myelogram. Five patients had a CT myelogram, which identified a dural leak in all patients and localized the leak in four of five patients. All patients underwent an epidural blood patch, which resolved the pain in five patients. One patient without relief underwent revision surgery with removal of a medially placed screw and fibrin glue placement resolving symptoms.

CONCLUSIONS

Postoperative dural leaks associated with PSF may present in a delayed fashion. The majority of leaks were not associated with screw malposition. In diagnosing patients with suspected LPDL, we suggest brain MRI with contrast as a first step. Most patients with pachymeningeal enhancement shown on contrast brain MRI had dural leaks that were identified through CT myelograms. For patients with a dural leak, if there is no disruption from screws, a blood patch appears to be an effective treatment.

LEVEL OF EVIDENCE

IV.

Real-world effectiveness of ixazomib combined with lenalidomide and dexamethasone in relapsed/refractory multiple myeloma: the REMIX study

Ixazomib (IXA) is an oral proteasome inhibitor (PI) used in combination with lenalidomide and dexamethasone (IXA-Rd) for patients with relapsed and/or refractory multiple myeloma (RRMM). The REMIX study is one of the largest prospective, real-world analysis of the effectiveness of IXA-Rd in the setting of RRMM. Conducted in France between August 2017 and October 2019, the REMIX study, a non-interventional prospective study, included 376 patients receiving IXA-Rd in second line or later and followed for at least 24 months. Primary endpoint was the median progression-free survival (mPFS). Median age was 71 years (Q1-Q3 65.0 - 77.5) with 18.4% of participants older than 80 years. IXA-Rd was initiated in L2, L3 and L4 + for 60.4%, 18.1% and 21.5%, respectively. mPFS was 19.1 months (95% CI [15.9, 21.5]) and overall response rate (ORR) was 73.1%. mPFS was 21.5, 21.9 and 5.8 months in patients receiving IXA-Rd as L2, L3, L4 + respectively. Among patients receiving IXA-Rd in L2 and L3, mPFS was similar for patients previously exposed to lenalidomide (19.5 months) than for those lenalidomide naive (not exposed, 22.6 months, p = 0.29). mPFS was 19.1 months in patients younger than 80 years and 17.4 months in those 80 years or older (p = 0.06) with similar ORR (72.4% and 76.8%) in both subgroups. Adverse events (AEs) were reported in 78.2% of patients including 40.7% of treatment-related AE. IXA discontinuation was due to toxicity in 21% of patients. To conclude, the results of the REMIX study are consistent with the results of Tourmaline-MM1 and confirm the benefit of IXA-Rd combination in real life. It shows the interest of IXA-Rd in an older and frailer population, with an acceptable effectiveness and tolerance.

Quantitative Sensory Changes Following Posterior Spinal Fusion to Treat Adolescent Idiopathic Scoliosis

BACKGROUND

Sensory changes surrounding the incision frequently develop after posterior spinal fusion (PSF) to treat adolescent idiopathic scoliosis (AIS). Anecdotally, patients may experience sensory changes on the chest wall. Such postsurgical sensory changes are not well described quantitatively. This study aims to evaluate the presence, intensity, and duration of mechanical sensory changes in AIS patients postoperatively.

METHODS

A prospective cohort of AIS patients, 10 to 21 years old, was followed. Quantitative sensory testing (QST) included touch detection threshold [mechanical detection threshold (MDT)] and pain detection threshold (MPT), using VonFrey monofilaments and pinprick stimulators. QST was performed at 3 sites at T6: the right and left chest at the nipple line and adjacent to the incision below the inferior angle of the scapula. QST at the thenar eminence was the control. QST was collected at baseline, 3 days, 1, and 6 months postoperative.

RESULTS

Thirty-four patients (21% males; mean age: 14.9 years old; median preoperative curve: 58 degrees) completed all testing. Mean deformity correction was 64% (SD: 10.4). Adjacent to the incision site, MDT was significantly higher compared with baseline at 3 days and 1 month ( P < 0.001) but not at 6 months ( P = 0.19), whereas MPT was significantly higher at 3 days, ( P < 0.001), 1 month ( P < 0.001), and 6 months ( P = 0.001). For the chest wall in all patients, MPT was higher on the left chest at 3 days ( P = 0.04) and on the right chest at 3 days ( P = 0.022) and 1 month ( P = 0.05). For patients with right-sided curves, MDT ( P = 0.01) and MPT ( P = 0.015) overall were significantly higher on the concave side (left) chest postoperatively.

CONCLUSIONS

PSF is associated with sensory disturbances that are detectable within days, persist at 1 month, and improve at 6 months postoperatively adjacent to the incision and on the chest wall. We suspect that these sensory changes are transient. Describing postoperative sensory changes will help us better set postoperative expectations for patients undergoing PSF.

LEVEL OF EVIDENCE

Level I.

Outcomes and Complications in Management of Congenital Myopathy Early-Onset Scoliosis

BACKGROUND

Congenital myopathies (CMs) are complex conditions often associated with early-onset scoliosis (EOS). The purpose of this study was to investigate radiographic outcomes in CM patients undergoing EOS instrumentation as well as complications. Secondarily, we sought to compare these patients to a population with higher prevalence, cerebral palsy (CP) EOS patients.

METHODS

This is a retrospective study of a prospectively collected multicenter registry. The registry was queried for EOS patients with growth-sparing instrumentation (vertical expandable prosthetic titanium ribs, magnetically controlled growing rods, traditional growing rod, or Shilla) and a CM or CP diagnosis with minimum 2 years follow-up. Outcomes included major curve magnitude, T1-S1 height, kyphosis, and complications.

RESULTS

Sixteen patients with CM were included. Six (37.5%) children with CM experienced 11 complications by 2 years. Mean major curve magnitude for CM patients was improved postoperatively and maintained at 2 years (P<0.01), with no significant increase in T1-S1 height or maximum kyphosis(P>0.05). Ninety-seven patients with CP EOS were included as a comparative cohort. Fewer CP patients required baseline respiratory support compared with CM patients (20.0% vs. 92.9%, P<0.01). Fifty-four (55.7%) CP patients experienced a total of 105 complications at 2 years. There was no evidence that the risk of complication or radiographic outcomes differs between cohorts at 2 years, though CP EOS patients experienced significant improvement in all measurements at 2 years.

CONCLUSIONS

EOS CM children face a high risk of complication after growing instrumentation, with similar curve correction and risk of complication to CP patients.

LEVEL OF EVIDENCE

Level III.

Does bracing for adolescent idiopathic scoliosis affect operative results?

STUDY DESIGN

Retrospective comparative study.

OBJECTIVES

We hypothesize that preoperative bracing for idiopathic scoliosis results in increased stiffness, as measured by reduced correction on bending films, ultimately leading to decreased surgical correction. Bracing is the primary nonoperative treatment for immature AIS patients with mild to moderate curves. For patients who fail bracing and proceed to operative intervention, it is unknown whether their nonoperative treatment impacts their surgical results.

METHODS

We conducted a single-center, retrospective, comparative study on 181 consecutive adolescent idiopathic scoliosis patients, aged 11-17 years, who underwent posterior spine fusion between 2011 and 2013. Patient flexibility was measured as percent change in the curve angle of the spine from standing to supine bend. Overall curve correction was calculated as the preoperative to postoperative change in standing coronal measure divided by the preoperative measurement and reported as a percentage.

RESULTS

One hundred and twelve subjects (62%) underwent bracing prior to fusion. Braced patients had similar preoperative major Cobb angles than unbraced patients (56.5 vs 59.0, p = 0.07). Preoperatively, braced patients achieved less primary curve correction in bending films (33.6%) than unbraced patients (40.6%, p = 0.003). Postoperatively, Cobb angle correction was not different between the braced (75.7%) and unbraced group (77.2%) overall (p = 0.41). There was no difference in blood loss (p = 0.14) or surgical time (p = 0.96) between braced and unbraced groups when adjusted for surgeon and number of levels fused.

CONCLUSIONS

While braced patients may demonstrate less preoperative flexibility, there is no evidence that braced patients experience decreased curve correction compared to unbraced patients. Bracing treatment did not impact operative results, as indicated by similar Cobb angle correction, estimated blood loss, and surgical time in both groups.

LEVEL OF EVIDENCE

III.

Survey to describe variability in early onset scoliosis cast practices

PURPOSE

To investigate paediatric orthopaedists' cast practices for early onset scoliosis regarding patient selection, cast application, radiographic evaluation, treatment cessation and adjunctive bracing.

METHODS

A casting survey was distributed to all paediatric orthopaedists in Children's Spine and Growing Spine Study Groups (n = 92). Questions included physician and patient characteristics, technique, treatment, outcomes, radiographic measurements and comparison to other treatments. A total of 55 orthopaedists (60%) responded, and descriptive statistics were calculated on the subset who cast (n = 45).

RESULTS

A majority of respondents use cast treatment for idiopathic and syndromic scoliosis patients, but not for neuromuscular or congenital scoliosis patients. Major curve angle ranked most important in orthopaedists' decision to commence cast treatment, in comparison with rib-vertebra angle difference or clinical observations. The major curve angle threshold to initiate casting was a median of 30° (20° to 70°), and the minimum patient age was median ten months (3 to 24). First in-cast and out-of-cast radiographs are taken standing, supine, awake, under anesthesia and/or in traction. In all, 58% consistently cast over or under the arm, while 44% vary position by patient. Respondents were divided about the use of a brace after cast treatment: 22% do not prescribe a brace, 31% always do and 36% do in some patients.

CONCLUSIONS

Future multicentre research studies must standardize radiographic practices and consider age and major curve angle at cast initiation and termination, scoliosis aetiology, shoulder position and treatment duration. Practices need to be aligned or compared in these areas in order to distinguish what makes for the best cast treatment possible.Level of Evidence: V, Expert opinion.

Safe and prolonged survival with long-term exposure to pomalidomide in relapsed/refractory myeloma

BACKGROUND

The IFM2009-02 trial studied pomalidomide (4 mg daily, 21/28 versus 28/28) and dexamethasone in very advanced relapsed or refractory multiple myeloma (RRMM). We observed that 40% of patients had a prolonged progression-free survival (PFS) and subsequently overall survival (OS). We sought to analyze the characteristics of these patients and study the effect of long exposure to pomalidomide.

DESIGN

We separated the studied population into two groups: 3 months to 1 year (<1 year) and more than 1 year (≥1 year) of treatment with pomalidomide and dexamethasone based on clinical judgment and historical control studies. We then analyzed the characteristics of patients according to duration of treatment.

RESULTS

The overall response rate (ORR) for the <1-year group was 43%, the median PFS 4.6 months [95% confidence interval (95% CI) 3.8-6.4] with only 6% at 12 months, and the median OS was 15 months (11.7-20.3) and 40% at 18 months. For the ≥1-year group, the response rate and survival were strikingly different, ORR at 83%, median PFS 20.7 months (14.7-35.4), median OS not reached, and 91% at 18 months.

CONCLUSION

Pomalidomide and dexamethasone favored prolonged and safe exposure to treatment in 40% of heavily treated and end-stage RRMM, a paradigm shift in the natural history of RRMM characterized with a succession of shorter disease-free intervals and ultimately shorter survival. Although an optimization of pomalidomide-dexamethasone regimen is warranted in advanced RRMM, we claim that pomalidomide has proven once more to change the natural history of myeloma in this series, which should be confirmed in a larger study.

[Pomalidomide for multiple myeloma]

Once characterized by a very poor outcome, multiple myeloma (MM) now has a significantly prolonged survival, with major improvements allowed by the use of "novel agents": proteasome inhibitors (first-in-class bortezomib) and immunomodulatory compounds (IMiDs; first-in-class thalidomide and lenalidomide). However, the vast majority - if not all - of patients with MM ultimately end up being refractory to all existing drugs, including these efficient novel agents. There is a clear unmet medical need in this situation, which warrants the development of the next generation of proteasome inhibitors and IMiDs, as well as new drug classes. This review focuses on pomalidomide, the next generation IMiD, recently approved by the US FDA and the EMA for patients with relapsed or refractory MM who have received at least two prior therapies, including lenalidomide and bortezomib, and have demonstrated disease progression on their last therapy.

Proximal Junctional Kyphosis After Vertical Expandable Prosthetic Titanium Rib Insertion

STUDY DESIGN

Retrospective review of patients who had undergone vertical expandable prosthetic titanium rib (VEPTR) treatment at a single institution.

OBJECTIVES

To evaluate whether clinically significant proximal junctional kyphosis (PJK) occurs after VEPTR insertion.

SUMMARY OF BACKGROUND DATA

PJK is a potential problem after posterior spinal instrumentation and fusion. PJK after VEPTR insertion has not been well-described.

METHODS

A total of 68 patients underwent VEPTR treatment between 1999 and 2009. Diagnosis, age at time of VEPTR insertion, location of VEPTR anchors, preoperative and postoperative scoliosis, T2-T12 kyphosis and PJK, time from VEPTR insertion to development of PJK, revision procedure for significant PJK, change in PJK after the revision procedure, and PJK at final follow-up were recorded.

RESULTS

Four patients developed PJK (6%). One patient had congenital scoliosis with rib fusions, 1 had scoliosis associated with a syndrome, and 2 had neuromuscular scoliosis. Mean follow-up was 5.7 years. Average T2-T12 kyphosis and PJK before VEPTR insertion were 77° and 14°, respectively. Mean T2-T12 kyphosis and PJK after VEPTR insertion were 63° and 33°, respectively. Average T2-T12 kyphosis and PJK before the recommended revision procedure for treatment of PJK were 89° and 53°, respectively. All patients developed PJK within the first year after VEPTR insertion. Two patients underwent revision to growing rods. One of these patients had preoperative halo-gravity traction. Mean PJK in these 2 patients improved from 39° to 18° after revision and remained stable at 19° at an average follow-up of 2.9 years.

CONCLUSIONS

PJK after VEPTR insertion can occur. Patients with preoperative thoracic hyperkyphosis may be at higher risk. PJK can develop within the first year of VEPTR treatment, and can become progressive and severe enough to require complex interventions. In this small case series, patients were revised to growing rods.

Deletion of the 1p32 region is a major independent prognostic factor in young patients with myeloma: the IFM experience on 1195 patients

Deletions of the 1p region appear as a pejorative prognostic factor in multiple myeloma patients (especially 1p22 and 1p32 deletions) but there is a lack of data on the real impact of 1p abnormalities on an important and homogeneous group of patients. To address this issue we studied by fluorescence in situ hybridization (FISH) the incidence and prognostic impact of 1p22 and 1p32 deletions in 1195 patients from the IFM (Institut Francophone du Myélome) cell collection. Chromosome 1p deletions were present in 23.3% of the patients (271): 15.1% (176) for 1p22 and 7.3% (85) for 1p32 regions. In univariate analyses, 1p22 and 1p32 appeared as negative prognostic factors for progression-free survival (PFS): 1p22: 19.8 months vs 33.6 months (P<0.001) and 1p32: 14.4 months vs 33.6 months (P<0.001); and overall survival (OS): 1p22: 44.2 months vs 96.8 months (P=0.002) and 1p32: 26.7 months vs 96.8 months (P<0.001). In multivariate analyses, 1p22 and 1p32 deletions still appear as independent negative prognostic factors for PFS and OS. In conclusion, our data show that 1p22 and 1p32 deletions are major negative prognostic factors for PFS and OS for patients with MM. We thus suggest that 1p32 deletion should be tested for all patients at diagnosis.

[Petrous plasmacytoma revealed by a painful peripheral facial palsy]

INTRODUCTION

The classical hypothesis of Bell's palsy, tempting in cases of peripheral facial palsy of rapid onset, must nevertheless be evoked with caution particularly if an intense pain is present, which should lead to search for a tumor of the skull base, especially the petrous bone.

CASE REPORT

A 43-year-old man presented a peripheral facial palsy of rapidly progressive onset. A petrous bone tumor was diagnosed on the CT scan, which revealed an aspect of a glomic tumor or a metastatic lesion. The final histological diagnosis was plasmacytoma.

DISCUSSION

This type of tumor has been rarely reported in this location. The radiological features are not specific at all, underlying the importance of searching for some associated signs such as a monoclonal protein and performing a histological examination when the firm diagnosis of a systemic disease like multiple myeloma has not been possible.

Lateral entry compared with medial and lateral entry pin fixation for completely displaced supracondylar humeral fractures in children. A randomized clinical trial

BACKGROUND

Closed reduction and percutaneous pin fixation is the treatment of choice for completely displaced (type-III) extension supracondylar fractures of the humerus in children, although controversy persists regarding the optimal pin-fixation technique. The purpose of this study was to compare the efficacy of lateral entry pin fixation with that of medial and lateral entry pin fixation for the operative treatment of completely displaced extension supracondylar fractures of the humerus in children.

METHODS

This prospective, randomized clinical trial had sufficient power to detect a 10% difference in the rate of loss of reduction between the two groups. The techniques of lateral entry and medial and lateral entry pin fixation were standardized in terms of the pin location, the pin size, the incision and position of the elbow used for medial pin placement, and the postoperative course. The primary study end points were a major loss of reduction and iatrogenic ulnar nerve injury. Secondary study end points included radiographic measurements, clinical alignment, Flynn grade, elbow range of motion, function, and complications.

RESULTS

The lateral entry group (twenty-eight patients) and the medial and lateral entry group (twenty-four patients) were similar in terms of mean age, sex distribution, and preoperative displacement, comminution, and associated neurovascular status. No patient in either group had a major loss of reduction. There was no significant difference between the rates of mild loss of reduction, which occurred in six of the twenty-eight patients treated with lateral entry and one of the twenty-four treated with medial and lateral entry (p = 0.107). There were no cases of iatrogenic ulnar nerve injury in either group. There were also no significant differences (p > 0.05) between groups with respect to the Baumann angle, change in the Baumann angle, humerocapitellar angle, change in the humerocapitellar angle, Flynn grade, carrying angle, elbow flexion, elbow extension, total elbow range of motion, return to function, or complications.

CONCLUSIONS

With use of the specific techniques employed in this study, both lateral entry pin fixation and medial and lateral entry pin fixation are effective in the treatment of completely displaced (type-III) extension supracondylar fractures of the humerus in children.

LEVEL OF EVIDENCE

Therapeutic Level I. See Instructions to Authors for a complete description of levels of evidence.

Respiratory status deterioration during G-CSF-induced neutropenia recovery

Exacerbation of prior pulmonary involvement may occur during neutropenia recovery. Granulocyte colony-stimulating factor (G-CSF)-related pulmonary toxicity has been documented in cancer patients, and experimental models suggest a role for G-CSF in acute lung injury during neutropenia recovery. We reviewed 20 cases of noncardiac acute respiratory failure during G-CSF-induced neutropenia recovery. Half the patients had received hematopoietic stem cell transplants. All patients experienced pulmonary infiltrates during neutropenia followed by respiratory status deterioration coinciding with neutropenia recovery. Neutropenia duration was 10 (4–22) days, and time between respiratory symptoms and the first day with more than 1000 leukocytes/mm³ was 1 (−0.5 to 2) day. Of the 20 patients, 16 received invasive or noninvasive mechanical ventilation, including 14 patients with acute respiratory distress syndrome (ARDS). Five patients died, with refractory ARDS. In patients with pulmonary infiltrates during neutropenia, G-CSF-induced neutropenia recovery carries a risk of respiratory status deterioration with acute lung injury or ARDS. Clinicians must maintain a high index of suspicion for this diagnosis, which requires eliminating another cause of acute respiratory failure, G-CSF discontinuation and ICU transfer for early supportive management including diagnostic confirmation and noninvasive mechanical ventilation.

Waterproof casts for immobilization of children's fractures and sprains

This study was designed to determine the efficacy of waterproof cast-lining materials in children with short-arm, long-arm, and short-leg casts. Eligible patients had healing fractures 2 weeks after reduction, stable fractures requiring no reduction, or sprains. A total of 165 waterproof-lined casts were applied and 124 children and parents completed a survey (76.9%) upon cast removal. Results revealed 79% very satisfied, 21% satisfied, and 0% dissatisfied. There were 16 (12.9%) minor skin integrity issues. Waterproof casts in stable fractures and sprains allow acceptable immobilization with no significant associated unusual risk and allow children to resume their usual recreational water activities and hygiene regimen without risk of adverse results.

Midodrine for the management of orthostatic hypotension in patients with spinal cord injury: A case report

A 21-year-old man sustained anterior displacement and a burst fracture of C7 in a motor vehicle crash. He underwent anterior corpectomy, decompression, fusion of C6-T1 vertebrae, and halo placement. The American Spinal Injury Association grade of his spinal cord injury (SCI) was C6 C tetraplegia. Severe orthostatic hypotension in the upright position complicated the patient's rehabilitation program. Midodrine was prescribed, and other medications with possible adverse effects were adjusted. Significant improvement after taking midodrine was reflected in the orthostatic vital signs and symptoms, as well as in FIM instrument scores. Staff noted improvements with therapy participation and functional status. The patient tolerated the midodrine well and had no significant side effects.

Transoesophageal echocardiography during scoliosis repair: comparison with CVP monitoring

PURPOSE

Accurate haemodynamic assessment during surgical repair of scoliosis is crucial to the care of the patient. The purpose of this study was to compare transoesophageal echocardiography (TEE) with central venous pressure monitoring in patients with spinal deformities requiring surgery in the prone position.

METHODS

Twelve paediatric patients undergoing corrective spinal surgery for scoliosis/kyphosis in the prone position were studied. Monitoring included TEE, intra-arterial and central venous pressure monitoring (CVP). Haemodynamic assessment was performed prior to and immediately after positioning the patient prone on the Relton-Hall table. Data consisted of mean arterial blood pressure (mBP), heart rate (HR), CVP, left ventricular end-systolic and end-diastolic diameters (LVESD and LVEDD respectively) and fractional shortening (FS). Right ventricular (RV) function and tricuspid regurgitation (TR) were assessed qualitatively. Analysis was performed using descriptive statistics, Student's t test, sign rank, and correlation analysis.

RESULTS

There was an increase in CVP (8.7 mmHg to 17.7 mmHg; P < .01), and decreases in LVEDD (37.1 mm to 33.2 mm; P < .05), and mean blood pressure (75.0 mmHg to 65.7 mmHg; P < .05) when patients were placed in the prone position. Fractional shortening, LVESD, and HR did not change from the supine to the prone position. Right ventricular systolic function and tricuspid regurgitation were unchanged.

CONCLUSION

These data indicate that the CVP is a misleading monitor of cardiac volume in patients with kyphosis/scoliosis in the prone position. This is consistent with previous studies. In this clinical situation, TEE may be a more useful monitoring tool to assess on-line ventricular size and function.

Segmental spinal dysgenesis

Segmental spinal dysgenesis is characterized by focal agenesis or dysgenesis of the lumbar or thoracolumbar spine, with focal abnormality of the underlying spinal cord and nerve roots. Children are symptomatic at birth with lower limb deformities and neurological deficits that may be segmental. Myelography and computed tomography disclose hypoplastic or absent vertebrae and atrophic or absent neural elements adjacent to the bony deformity; the spinal column distal to the abnormality may be partially bifid, but is otherwise normal. Spinal ultrasonography was a helpful diagnostic adjunct in one patient. Surgery may be helpful in decompressing partially functioning spinal cord or nerve roots, but may exaggerate the tendency toward spinal instability. The embryology of this abnormality is not clear, but two children had other anomalies suggesting a spinal dysraphic syndrome, and its cause is probably related to a segmental maldevelopment of the neural tube.

Independent Action of Thymus and Bone Marrow Cells During the Secondary Response of Direct Plaque-Forming Cells

Thymocytes and bone marrow cells from normal mice or from mice primed with SRBC were used to repopulate heavily irradiated mice. The recipients were challenged with SRBC and the PFC formed in their spleens were enumerated. The thymus-marrow synergism characteristic of unprimed cells was not found when primed cells were used in the restoring inoculum. Thymocytes and marrow cells from primed mice were each capable of restoring immunocompetence in the recipients, and in contrast with the corresponding cells from unprimed animals they appeared to react immunologically as independent units.

Effects of number of alternatives on the psychological refractory period

The effects of changing the number of choices in the first response on “psychological refractoriness” were found to be partially consistent with intermittency theory but modifications may be needed to explain the results when the number of choices in the second response is increased.