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Wilson Z. Ray

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Susan E. Mackinnon, Andrew Yee, and Wilson Z. Ray

Spinal cord injury (SCI) remains a significant public health problem. Despite advances in understanding of the pathophysiological processes of acute and chronic SCI, corresponding advances in translational applications have lagged behind. Nerve transfers using an expendable nearby motor nerve to reinnervate a denervated nerve have resulted in more rapid and improved functional recovery than traditional nerve graft reconstructions following a peripheral nerve injury. The authors present a single case of restoration of some hand function following a complete cervical SCI utilizing nerve transfers.

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Rory K. J. Murphy, Wilson Z. Ray, and Susan E. Mackinnon

Complete loss of median nerve motor function is a rare but devastating injury. Loss of median motor hand function and upper-extremity pronation can significantly impact a patient's ability to perform many activities of daily living independently. The authors report the long-term follow-up in a case of median nerve motor fiber transection that occurred during an arthroscopic elbow procedure, which was then treated with multiple nerve transfers. Motor reconstruction used the nerves to the supinator and extensor carpi radialis brevis to transfer to the anterior interosseous nerve and pronator. Sensory sensation was restored using the lateral antebrachial cutaneous (LABC) nerve to transfer to a portion of the sensory component of the median nerve, and a second cable of LABC nerve as a direct median nerve sensory graft. The patient ultimately recovered near normal motor function of the median nerve, but had persistent pain symptoms 4 years postinjury.

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Matthew R. MacEwan, Paul Gamble, Manu Stephen, and Wilson Z. Ray

OBJECTIVE

Electrical stimulation of peripheral nerve tissue has been shown to accelerate axonal regeneration. Yet existing methods of applying electrical stimulation to injured peripheral nerves have presented significant barriers to clinical translation. In this study, the authors examined the use of a novel implantable wireless nerve stimulator capable of simultaneously delivering therapeutic electrical stimulation of injured peripheral nerve tissue and providing postoperative serial assessment of functional recovery.

METHODS

Flexible wireless stimulators were fabricated and implanted into Lewis rats. Thin-film implants were used to deliver brief electrical stimulation (1 hour, 20 Hz) to sciatic nerves after nerve crush or nerve transection-and-repair injuries.

RESULTS

Electrical stimulation of injured nerves via implanted wireless stimulators significantly improved functional recovery. Brief electrical stimulation was observed to increase the rate of functional recovery after both nerve crush and nerve transection-and-repair injuries. Wireless stimulators successfully facilitated therapeutic stimulation of peripheral nerve tissue and serial assessment of nerve recovery.

CONCLUSIONS

Implantable wireless stimulators can deliver therapeutic electrical stimulation to injured peripheral nerve tissue. Implantable wireless nerve stimulators might represent a novel means of facilitating therapeutic electrical stimulation in both intraoperative and postoperative settings.

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Jan Fridén and Andreas Gohritz

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Wilson Z. Ray, Chester K. Yarbrough, Andrew Yee, and Susan E. Mackinnon

The surgical management of lower brachial plexus injuries remains a challenging problem. Although nerve transfers have improved clinical outcomes following brachial plexus injuries, the majority of work has focused on upper trunk injuries. Complete lower plexus injuries often lack suitable donors for either nerve or tendon transfers. The authors describe their experience with isolated lower trunk injuries utilizing the nerve to the brachialis to reinnervate the anterior interosseous nerve.

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Wilson Z. Ray, Vijay M. Ravindra, Meic H. Schmidt, and Andrew T. Dailey

Object

Pelvic fixation is a crucial adjunct to many lumbar fusions to avoid L5–S1 pseudarthrosis. It is useful for treatment of kyphoscoliosis, high-grade spondylolisthesis, L5–S1 pseudarthrosis, sacral tumors, lumbosacral dislocations, and osteomyelitis. The most popular method, iliac fixation, has drawbacks including hardware prominence, extensive muscle dissection, and the need for connection devices. S-2 alar iliac fixation provides a useful primary or salvage alternative. The authors describe their techniques for using stereotactic navigation for screw placement.

Methods

The O-arm Surgical Imaging System allowed for CT-quality multiplanar reconstructions of the pelvis, and registration to a StealthStation Treon provided intraoperative guidance. The authors describe their technique for performing computer-assisted S-2 alar iliac fixation for various indications in 18 patients during an 18-month period.

Results

All patients underwent successful bilateral placement of screws 80–100 mm in length. All placements were confirmed with a second multiplanar reconstruction. One screw was moved because of apparent anterior breach of the ilium. There were no immediate neurological or vascular complications due to screw placement. The screw length required additional instruments including a longer pedicle finder and tap.

Conclusions

Stereotactic guidance to navigate the placement of distal pelvic fixation with bilateral S-2 alar iliac fixation can be safely performed in patients with a variety of pathological conditions. Crossing the sacroiliac joint, choosing trajectory, and ensuring adequate screw length can all be enhanced with 3D image guidance. Long-term outcome studies are underway, specifically evaluating the sacroiliac joint.

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Jawad M. Khalifeh, Christopher F. Dibble, Ammar H. Hawasli, and Wilson Z. Ray

OBJECTIVE

The Patient-Reported Outcomes Measurement Information System (PROMIS) is an adaptive, self-reported outcomes assessment tool that utilizes item response theory and computer adaptive testing to efficiently and precisely evaluate symptoms and perceived health status. Efforts to implement and report PROMIS outcomes in spine clinical practice remain limited. The objective of this retrospective cohort study is to evaluate the performance and psychometric properties of PROMIS physical function (PF) and pain interference (PI) among patients undergoing spine surgery.

METHODS

The authors identified all patients who underwent spine surgery at their institution between 2016 and 2018, and for whom there was retrievable PROMIS data. Descriptive statistics were calculated to summarize demographics, operative characteristics, and patient-reported outcomes. Assessments were evaluated preoperatively, and postoperatively within 2 months (early), 6 months (intermediate), and up to 2 years (late). Pairwise change scores were calculated to evaluate within-subjects differences and construct responsiveness over time. Pearson’s correlation coefficients were used to evaluate the association between PROMIS PF and PI domains. Subgroup analysis was performed based on the primary diagnoses of cervical radiculopathy, cervical myelopathy, or lumbar degenerative disease.

RESULTS

A total of 2770 patients (1395 males, 50.4%) were included in the analysis. The mean age at the time of surgery was 57.3 ± 14.4 years. Mean postoperative follow-up duration was 7.6 ± 6.2 months. Preoperatively, patients scored an average 15.1 ± 7.4 points below the normative population (mean 50 ± 10 points) in PF, and 15.8 ± 6.8 points above the mean in PI. PROMIS PF required a mean of 4.1 ± 0.6 questions and median 40 seconds (interquartile range [IQR] 29–58 seconds) to be completed, which was similar to PI (median 4.3 ± 1.1 questions and 38 seconds [IQR 27–59 seconds]). Patients experienced clinically meaningful improvements in PF and PI, which were sustained throughout the postoperative course. PROMIS instruments were able to capture anticipated changes in PF and PI, although to a lesser degree in PF early postoperatively. There was a strong negative correlation between PROMIS PF and PI scores at baseline (Pearson’s r = −0.72) and during follow-up appointments (early, intermediate, and late |r| > 0.6, each). Subgroup analysis demonstrated similar results within diagnostic groups compared to the overall cohort. However, the burden of PF limitations and PI was greater within the lumbar spine disease subgroup, compared to patients with cervical radiculopathy and myelopathy.

CONCLUSIONS

Patients receiving care at a tertiary spine surgery outpatient clinic experience significant overall disability and PI, as measured by PROMIS PF and PI computer adaptive tests. PROMIS PF and PI health domains are strongly correlated, responsive to changes over time, and facilitate time-efficient evaluations of perceived health status outcomes in patients undergoing spine surgery.

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Christopher F. Dibble, Saad Javeed, Justin K. Zhang, Brenton Pennicooke, Wilson Z. Ray, and Camilo Molina

BACKGROUND

Traumatic atlantoaxial rotatory subluxation after type 3 odontoid fracture is an uncommon presentation that may require complex intraoperative reduction maneuvers and presents challenges to successful instrumentation and fusion.

OBSERVATIONS

The authors report a case of a 39-year-old female patient who sustained a type 3 odontoid fracture. She was neurologically intact and managed in a rigid collar. Four months later, she presented again after a second trauma with acute torticollis and type 2 atlantoaxial subluxation, again neurologically intact. Serial cervical traction was placed with minimal radiographic reduction. Ultimately, she underwent intraoperative reduction, instrumentation, and fusion. Freehand C1 lateral mass reduction screws were placed, then C2 translaminar screws, and finally lateral mass screws at C3 and C4. The C2–4 instrumentation was used as bilateral rod anchors to reduce the C1 lateral mass reduction screws engaged onto the subluxated atlantodental complex. As a final step, cortical allograft spacers were inserted at C1–2 under compression to facilitate long-term stability and fusion.

LESSONS

This is the first description of a technique using extended tulip cervical reduction screws to correct traction-irreducible atlantoaxial subluxation. This case is a demonstration of using intraoperative tools available for the spine surgeon managing complex cervical injuries requiring intraoperative reduction that is resistant to traction reduction.

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Jacob K. Greenberg, Derek S. Brown, Margaret A. Olsen, and Wilson Z. Ray

OBJECTIVE

The Affordable Care Act expanded Medicaid eligibility in many states, improving access to some forms of elective healthcare in the United States. Whether this effort increased access to elective spine surgical care is unknown. This study’s objective was to evaluate the impact of Medicaid expansion under the Affordable Care Act on the volume and payer mix of elective spine surgery in the United States.

METHODS

This study evaluated elective spine surgical procedures performed from 2011 to 2016 and included in the all-payer State Inpatient Databases of 10 states that expanded Medicaid access in 2014, as well as 4 states that did not expand Medicaid access. Adult patients aged 18–64 years who underwent elective spine surgery were included. The authors used a quasi-experimental difference-in-difference design to evaluate the impact of Medicaid expansion on hospital procedure volume and payer mix, independent of time-dependent trends. Subgroup analysis was conducted that stratified results according to cervical fusion, thoracolumbar fusion, and noninstrumented surgery.

RESULTS

The authors identified 218,648 surgical procedures performed in 10 Medicaid expansion states and 118,693 procedures performed in 4 nonexpansion states. Medicaid expansion was associated with a 17% (95% CI 2%–35%, p = 0.03) increase in mean hospital spine surgical volume and a 23% (95% CI −0.3% to 52%, p = 0.054) increase in Medicaid volume. Privately insured surgical volumes did not change significantly (incidence rate ratio 1.13, 95% CI −5% to 34%, p = 0.18). The increase in Medicaid volume led to a shift in payer mix, with the proportion of Medicaid patients increasing by 6.0 percentage points (95% CI 4.1–7.0, p < 0.001) and the proportion of private payers decreasing by 6.7 percentage points (95% CI 4.5–8.8, p < 0.001). Although the magnitude of effects varied, these trends were similar across procedure subgroups.

CONCLUSIONS

Medicaid expansion under the Affordable Care Act was associated with an economically and statistically significant increase in spine surgery volume and the proportion of surgical patients with Medicaid insurance, indicating improved access to care.