Browse

You are looking at 61 - 70 of 87 items for

  • By Author: Wang, Michael Y. x
Clear All
Restricted access

Matthew D. Cummock, Steven Vanni, Allan D. Levi, Yong Yu and Michael Y. Wang

Object

The minimally invasive transpsoas interbody fusion technique requires dissection through the psoas muscle, which contains the nerves of the lumbosacral plexus posteriorly and genitofemoral nerve anteriorly. Retraction of the psoas is becoming recognized as a cause of transient postoperative thigh pain, numbness, paresthesias, and weakness. However, few reports have described the nature of thigh symptoms after this procedure.

Methods

The authors performed a review of patients who underwent the transpsoas technique for lumbar spondylotic disease, disc degeneration, and spondylolisthesis treated at a single academic medical center. A review of patient charts, including the use of detailed patient-driven pain diagrams performed at equal preoperative and follow-up intervals, investigated the survival of postoperative thigh pain, numbness, paresthesias, and weakness of the iliopsoas and quadriceps muscles in the follow-up period on the ipsilateral side of the surgical approach.

Results

Over a 3.2-year period, 59 patients underwent transpsoas interbody fusion surgery. Of these, 62.7% had thigh symptoms postoperatively. New thigh symptoms at first follow-up visit included the following: burning, aching, stabbing, or other pain (39.0%); numbness (42.4%); paresthesias (11.9%); and weakness (23.7%). At 3 months postoperatively, these percentages decreased to 15.5%, 24.1%, 5.6%, and 11.3%, respectively. Within the patient sample, 44% underwent a 1-level, 41% a 2-level, and 15% a 3-level transpsoas operation. While not statistically significant, thigh pain, numbness, and weakness were most prevalent after L4–5 transpsoas interbody fusion at the first postoperative follow-up. The number of lumbar levels that were surgically treated had no clear association with thigh symptoms but did correlate directly with surgical time, intraoperative blood loss, and length of hospital stay.

Conclusions

Transpsoas interbody fusion is associated with high rates of immediate postoperative thigh symptoms. While larger, prospective studies are necessary to validate these findings, the authors found that half of the patients had symptom resolution at approximately 3 months postoperatively and more than 90% by 1 year.

Restricted access

Ricardo B. V. Fontes and Vincent C. Traynelis

Restricted access

Matthew J. McGirt, Scott L. Parker, Jason Lerner, Luella Engelhart, Tyler Knight and Michael Y. Wang

Object

Surgical site infection (SSI) after lumbar fusion results in significant patient morbidity and associated medical resource utilization. Minimally invasive (MI) techniques for posterior/transforaminal lumbar interbody fusion (P/TLIF) were introduced with the goals of smaller wounds, less tissue trauma, reduced blood loss, and quicker postoperative recovery, while maintaining comparable surgical results. Studies with sufficient power to directly compare the incidence of SSI following MI versus open P/TLIF procedures have been lacking. Furthermore, the direct medical cost associated with the treatment of SSI following the P/TLIF procedure is poorly understood and has not been adequately assessed. Thus, the aim in the present study was to determine the incidence of perioperative SSI in patients undergoing MI versus open P/TLIF and the direct hospital cost associated with the diagnosis and management of SSI after P/TLIF as reported in a large administrative database.

Methods

The authors retrospectively reviewed hospital discharge and billing records from the Premier Perspective Database for 2003 to 2009 to identify patients undergoing 1- or 2-level MI or open P/TLIF for lumbar spondylotic disease, disc degeneration, or spondylolisthesis. The ICD-9-CM procedure codes were used to identify patients undergoing P/TLIF and those experiencing SSI. Infection-related costs were obtained from the total costs incurred by the hospital for SSI-related care provided during inpatient or hospital outpatient encounters.

Results

Five thousand one hundred seventy patients undergoing P/TLIF were identified. Demographic profiles, including the Charlson Comorbidity Index, were similar between MI and open cohorts. Overall, 292 patients (5.6%) experienced an SSI with a mean direct cost of $15,817 per SSI. For 1-level MI versus open P/TLIF, the incidence of SSI (38 [4.5%] vs 77 [4.8%], p = 0.77) and the mean SSI-associated cost per P/TLIF ($684 vs $724, p = 0.680) were similar. For 2-level MI versus open P/TLIF, the incidence of SSI (27 [4.6%] vs 150 [7.0%], p = 0.037) and mean SSI-associated cost per P/TLIF ($756 vs $1140, p = 0.030) were both significantly lower among MI-treated patients. In a multivariate model that accounted for differences in demographics and patient severity, open fusion was associated with a strong trend of increased incidence of SSI as compared with MI fusion (OR 1.469, 95% CI 0.959–2.250).

Conclusions

In this multihospital study, the MI technique was associated with a decreased incidence of perioperative SSI and a direct cost savings of $38,400 per 100 P/TLIF procedure when used in 2-level fusion. There was no significant difference in the incidence of SSIs between the open and MI cohorts for 1-level fusion procedures. The results of this study provide further evidence of the reduced patient morbidity and health care costs associated with MI P/TLIF.

Restricted access

Michael Y. Wang and Spencer Block

As surgical techniques evolve, new intraoperative complications are prone to occur. With percutaneous spinal fixation, the control of implants and instruments can be a challenge when compared with open surgery, particularly if unintended instruments are retained or difficult to retrieve. In this report, the authors describe a case in which Jamshidi needle fragments broke within the vertebral body. Extraction of the fragments was accomplished using a small pedicle screw tap to first engage the retained metal and then to loosen the surrounding bone to allow retrieval and preservation of the anatomical structures needed to complete the intended operation. This technique may prove useful for the retrieval of deformable, cannulated metal pieces in minimally invasive surgery.

Full access

Patrick C. Hsieh and Michael Y. Wang

Full access

Michael Y. Wang and Michael Thambuswamy

Object

Ossification of the posterior longitudinal ligament (OPLL) is a disorder afflicting as many as 2% of East Asians. However, reports of OPLL in non-Asians have been sporadic in the medical literature. This study describes clinical and radiographic findings with OPLL in non-Asians at a tertiary care center treating a diverse multiethnic population.

Methods

Over a 6-year period, 43 patients not of East Asian descent presented to an urban tertiary medical center with OPLL. Patient data, including ethnicity, spinal cord function, Nurick grade, radiographic findings, OPLL subtype, and degree of cervical stenosis, were recorded.

Results

The average patient age was 59 years (range 32–92 years) with 18 women and 25 men. There were 22 Caucasian patients, 17 Hispanic patients, and 4 Black patients. With respect to the radiographic findings, OPLL morphology was continuous in 19, segmental in 17, mixed in 6, and other in 1. Average canal diameter was 7.6 mm (range 4.2–9.0 mm) at the most stenotic points. The mean Nurick grade was 2.95 at presentation, but 7 of the patients had OPLL identified incidentally and with early or minimal symptoms and signs of myelopathy.

Conclusions

Ossification of the posterior longitudinal ligament in non-Asians demonstrates similar demographic and radiographic characteristics as in East Asians. The representation of different ethnic groups mirrors the demographics of the medical center population in general, showing no specific predilection for particular ethnic groups. Surgical decompression in appropriately selected patients results in similar rates of improvement when compared with the Japanese literature.

Restricted access

Michael Y. Wang, Guillermo Pineiro and Praveen V. Mummaneni

Object

Percutaneous pedicle screws have recently become popularized for lumbar spinal fixation. However, successful anatomical hardware placement is highly dependent on intraoperative imaging. In traditional open surgery, stimulus-evoked electromyography (EMG) responses can be useful for detecting pedicle screw breaches. The use of insulated sleeves for percutaneous screws has allowed for EMG testing in minimally invasive surgery; however, no reports on the reliability of this testing modality have been published.

Methods

A total of 409 lumbar percutaneous pedicle screws were placed in 93 patients. Levels of instrumentation included L-1 (in 12 patients), L-2 (in 34), L-3 (in 44), L-4 (in 120), L-5 (in 142), and S-1 (in 57 patients). Intraoperative EMG stimulation thresholds were obtained using insulating sleeves over a metallic tap prior to final screw placement. Data were compared with postoperative fine-cut CT scans to assess pedicle screw placement. Data were collected prospectively and analyzed retrospectively.

Results

There were 5 pedicle breaches (3 medial and 2 lateral; 3 Grade 1 and 2 Grade 2 breaches) visualized on postoperative CT scans (1.2%). Two of these breaches were symptomatic. In 2 instances, intraoperative thresholds were the sole basis for screw trajectory readjustment, which resulted in proper placement on postoperative imaging. Thirty-five screw trajectories were associated with a threshold of less than 12 mA. However, all breaches were associated with thresholds of greater than 12 mA. Using thresholds below 12 mA as the indicator of a screw breach, this resulted in a sensitivity of 0.0, specificity of 90.3, positive predictive value of 0.0, and negative predictive value of 0.98. Utilizing a threshold of any decreased stimulus (< 20 mA) would have detected 60% of breaches, with a mean threshold of 16.25 mA.

Conclusions

While these data are limited by the low number of radiographic breaches, it appears that tap stimulation with an insulating sleeve may not be reliable for detecting low-grade radiographically breached pedicles using typical stimulation thresholds (< 12 mA). Imaging-based modalities remain more reliable for assessing percutaneous pedicle screw trajectories until more robust and sensitive electrophysiological testing methods can be devised.

Restricted access

Michael Y. Wang, Matthew D. Cummock, Yong Yu and Rikin A. Trivedi

Object

Minimally invasive spine (MIS) procedures are increasingly being recognized as equivalent to open procedures with regard to clinical and radiographic outcomes. These techniques are also believed to result in less pain and disability in the immediate postoperative period. There are, however, little data to assess whether these procedures produce their intended result and even fewer objective data to demonstrate that they are cost effective when compared with open surgery.

Methods

The authors performed a retrospective analysis of hospital charges for 1- and 2-level MIS and open posterior interbody fusion for lumbar spondylotic disease, disc degeneration, and spondylolisthesis treated at a single academic medical center. Patients presenting with bilateral neurological symptoms were treated with open surgery, and those with unilateral symptoms were treated with MIS. Overall hospital charges and surgical episode–related charges, length of stay (LOS), and discharge status were obtained from the hospital finance department and adjusted for multi-/single-level surgeries.

Results

During a 14-month period, 74 patients (mean age 55 years) were treated. The series included 59 single-level operations (75% MIS and 25% open), and 15 2-level surgeries (53% MIS and 47% open). The demographic profile, including age and Charlson Comorbidity Index, were similar between the 4 groups. The mean LOS for patients undergoing single-level surgery was 3.9 and 4.8 days in the MIS and open cases, respectively (p = 0.017). For those undergoing 2-level surgery, the mean LOS was 5.1 for MIS versus 7.1 for open surgery (p = 0.259). With respect to hospital charges, single-level MIS procedures were associated with an average of $70,159 compared with $78,444 for open surgery (p = 0.027). For 2-level surgery, mean charges totalled $87,454 for MIS versus $108,843 for open surgery (p = 0.071). For single-level surgeries, 5 and 20% of patients undergoing MIS and open surgery, respectively, were discharged to inpatient rehabilitation. For 2-level surgeries, the rates were 13 and 29%, respectively.

Conclusions

While hospital setting, treatment population, patient selection, and physician expectation play major roles in determining hospital charges and LOS, this pilot study at an academic teaching hospital shows trends for quicker discharge, reduced hospital charges, and lower transfer rates to inpatient rehabilitation with MIS. However, larger multicenter studies are necessary to validate these findings and their relevance across diverse US practice environments.

Restricted access

Daniel J. Hoh, Charles Y. Liu and Michael Y. Wang

Object

Effective methods for fixation of the axis include C1–2 transarticular and C-2 pedicle screw placement. Both techniques pose a risk of vertebral artery (VA) injury in patients with narrow pedicles or an enlarged, high-riding VA. Pars screws at C-2 avoid the pedicle, but can cause VA injury with excessively long screws. Therefore, the authors evaluated various entry points and trajectories to determine ideal pars screw lengths that avoid breaching the transverse foramen.

Methods

Both pars were studied on 50 CT scans (100 total). Various pars lengths were assessed using 2 entry points and 3 trajectories (6 measurements). Entry point A was the superior one-fourth of the lateral mass. Entry point B was 3-mm rostral to the inferior aspect of the lateral mass. Using entry points A and B, Trajectory 1 was the minimum distance to the transverse foramen; Trajectory 2 was the maximum distance to the transverse foramen; and Trajectory 3 was the steepest angle to the pars/C-2 superior facet junction without transverse foramen breach.

Results

The mean patient age was 46 ± 17 years, and 84% of the CT scans reviewed were obtained in men. There was no significant difference in right or left measurements. Entry point B demonstrated greater pars lengths for each trajectory compared with entry point A (p < 0.0001). For both entry points, Trajectory 3 provided the greatest pars length. Using Trajectory 3 with entry point B, 84, 95, and 99% had a pars length that measured ≥ 18, 16, and 14 mm, respectively. Using Trajectory 3 with Entry point A, only 41, 64, and 87% had a pars length that measured ≥ 18, 16, and 14 mm, respectively.

Conclusions

Using an entry point 3-mm rostral to the inferior edge of the lateral mass and a trajectory directed toward the superior facet/pars junction, 99% of partes interarticularis in this study would tolerate a 14-mm screw without breach of the transverse foramen.

Full access

Michael Y. Wang and Praveen V. Mummaneni

Object

Adult degenerative scoliosis can be a cause of intractable pain, decreased mobility, and reduced quality of life. Surgical correction of this problem frequently leads to substantial clinical improvement, but advanced age, medical comorbidities, osteoporosis, and the rigidity of the spine result in high surgical complication rates. Minimally invasive surgery is being applied to this patient population in an effort to reduce the high complication rates associated with adult deformity surgery.

Methods

A retrospective study of 23 patients was undertaken to assess the clinical and radiographic results with minimally invasive surgery for adult thoracolumbar deformity surgery. All patients underwent a lateral interbody fusion followed by posterior percutaneous screw fixation and possible minimally invasive surgical transforaminal lumbar interbody fusion if fusion near the lumbosacral junction was necessary. A mean of 3.7 intersegmental levels were treated (range 2–7 levels). The mean follow-up was 13.4 months.

Results

The mean preoperative Cobb angle was 31.4°, and it was corrected to 11.5° at follow-up. The mean blood loss was 477 ml, and the operative time was 401 minutes. The mean visual analog scale score improvement for axial pain was 3.96. Clear evidence of fusion was seen on radiographs at 84 of 86 treated levels, with no interbody pseudarthroses. Complications included 2 returns to the operating room, one for CSF leakage and the other for hardware pullout. There were no wound infections, pneumonia, deep venous thrombosis, or new neurological deficits. However, of all patients, 30.4% experienced new thigh numbness, dysesthesias, pain, or weakness, and in one patient these new symptoms were persistent.

Conclusions

The minimally invasive surgical treatment of adult deformities is a promising method for reducing surgical morbidity. Numerous challenges exist, as the surgical technique does not yet allow for all correction maneuvers used in open surgery. However, as the techniques are advanced, the applicability of minimally invasive surgery for this population will likely be expanded and will afford the opportunity for reduced complications.