Browse

You are looking at 1 - 10 of 23 items for

  • By Author: Oskouian, Rod J. x
Clear All
Restricted access

R. Shane Tubbs, Andrés A. Maldonado, Yolanda Stoves, Fabian N. Fries, Rong Li, Marios Loukas, Rod J. Oskouian and Robert J. Spinner

OBJECTIVE

The accessory nerve is frequently repaired or used for nerve transfer. The length of accessory nerve available is often insufficient or marginal (under tension) for allowing direct coaptation during nerve repair or nerve transfer (neurotization), necessitating an interpositional graft. An attractive maneuver would facilitate lengthening of the accessory nerve for direct coaptation. The aim of the present study was to identify an anatomical method for such lengthening.

METHODS

In 20 adult cadavers, the C-2 or C-3 connections to the accessory nerve were identified medial to the sternocleidomastoid (SCM) muscle and the anatomy of the accessory nerve/cervical nerve fibers within the SCM was documented. The cervical nerve connections were cut. Lengths of the accessory nerve were measured. Samples of the cut C-2 and C-3 nerves were examined using immunohistochemistry.

RESULTS

The anatomy and adjacent neural connections within the SCM are complicated. However, after the accessory nerve was “detethered” from within the SCM and following transection, the additional length of the accessory nerve increased from a mean of 6 cm to a mean of 10.5 cm (increase of 4.5 cm) after cutting the C-2 connections, and from a mean of 6 cm to a mean length of 9 cm (increase of 3.5 cm) after cutting the C-3 connections. The additional length of accessory nerve even allowed direct repair of an infraclavicular target (i.e., the proximal musculocutaneous nerve). The cervical nerve connections were shown not to contain motor fibers.

CONCLUSIONS

An additional length of the accessory nerve made available in the posterior cervical triangle can facilitate direct repair or neurotization procedures, thus eliminating the need for an interpositional nerve graft, decreasing the time/distance for regeneration and potentially improving clinical outcomes.

Full access

Marc Moisi, Christian Fisahn, Lara Tkachenko, Shiveindra Jeyamohan, Stephen Reintjes, Peter Grunert, Daniel C. Norvell, R. Shane Tubbs, Jeni Page, David W. Newell, Peter Nora, Rod J. Oskouian and Jens Chapman

OBJECTIVE

Posterior atlantoaxial stabilization and fusion using C-1 lateral mass screw fixation has become commonly used in the treatment of instability and for reconstructive indications since its introduction by Goel and Laheri in 1994 and modification by Harms in 2001. Placement of such lateral mass screws can be challenging because of the proximity to the spinal cord, vertebral artery, an extensive venous plexus, and the C-2 nerve root, which overlies the designated starting point on the posterior center of the lateral mass. An alternative posterior access point starting on the posterior arch of C-1 could provide a C-2 nerve root–sparing starting point for screw placement, with the potential benefit of greater directional control and simpler trajectory. The authors present a cadaveric study comparing an alternative strategy (i.e., a C-1 screw with a posterior arch starting point) to the conventional strategy (i.e., using the lower lateral mass entry site), specifically assessing the safety of screw placement to preserve the C-2 nerve root.

METHODS

Five US-trained spine fellows instrumented 17 fresh human cadaveric heads using the Goel/Harms C-1 lateral mass (GHLM) technique on the left and the posterior arch lateral mass (PALM) technique on the right, under fluoroscopic guidance. After screw placement, a CT scan was obtained on each specimen to assess for radiographic screw placement accuracy. Four faculty spine surgeons, blinded to the surgeon who instrumented the cadaver, independently graded the quality of screw placement using a modified Upendra classification.

RESULTS

Of the 17 specimens, the C-2 nerve root was anatomically impinged in 13 (76.5%) of the specimens. The GHLM technique was graded Type 1 or 2, which is considered “acceptable,” in 12 specimens (70.6%), and graded Type 3 or 4 (“unacceptable”) in 5 specimens (29.4%). In contrast, the PALM technique had 17 (100%) of 17 graded Type 1 or 2 (p = 0.015). There were no vertebral artery injuries found in either technique. All screw violations occurred in the medial direction.

CONCLUSIONS

The PALM technique showed statistically fewer medial penetrations than the GHLM technique in this study. The reason for this is not clear, but may stem from a more angulated ”up-and-in” screw direction necessary with a lower starting point.

Restricted access

Amir Ahmadian, Sean Verma, Gregory M. Mundis Jr., Rod J. Oskouian Jr., Donald A. Smith and Juan S. Uribe

Object

In this study the authors report on the clinical outcomes, safety, and efficacy of lateral retroperitoneal transpsoas minimally invasive surgery–lumbar interbody fusion (MIS-LIF) at the L4–5 disc space in patients with spondylolisthesis. This approach has become an increasingly popular means of fusion. Its most frequent complication is lumbar plexus injury. Reported complication rates at the L4–5 disc space vary widely in the literature, bringing into question the safety of MIS-LIF for the L4–5 region, especially in patients with spondylolisthesis.

Methods

The authors retrospectively reviewed prospectively acquired multicenter databases of patients with Grade I and II L4–5 spondylolisthesis who had undergone elective MIS-LIF between 2008 and 2011. Clinical follow-up had been scheduled for 1, 3, 6, 12, and 24 months postoperatively. Outcome measures included estimated blood loss, operative time, length of hospital stay, integrity of construct, complications, fusion rates, visual analog scale (VAS), Oswestry Disability Index (ODI), and 36-Item Short Form Health Survey (SF-36).

Results

Eighty-four patients with L4–5 MIS-LIF were identified, 31 of whom met the study inclusion criteria: 26 adults with Grade I and 5 adults with Grade II L4–5 spondylolisthesis who had undergone elective MIS-LIF and subsequent posterior percutaneous pedicle screw fixation without surgical manipulation of the posterior elements (laminectomy, foraminotomy, facetectomy). The study cohort consisted of 9 males (29%) and 22 females (71%) with an average age of 61.5 years. The mean total blood loss was 94 ml (range 20–250 ml). The mean hospital stay and follow-up were 3.5 days and 18.2 months, respectively. The average score on the ODI improved from 50.4 preoperatively to 30.9 at the last follow-up (p < 0.0001). The SF-36 score improved from 38.1 preoperatively to 59.5 at the last follow-up (p < 0.0001). The VAS score improved from 69.9 preoperatively to 38.7 at the last follow-up (p < 0.0001). No motor weakness or permanent deficits were documented in any patient. Correction of deformity did not have any neurological complications. All patients had improvement in anterolisthesis. Residual postoperative listhesis across cases was noted in 4 patients (12.9%). Transient anterior thigh numbness (Sensory Dermal Zone III) was noted in 22.5% of patients.

Conclusions

With its established surgical corridors through the retroperitoneum and psoas muscle, the MIS-LIF combined with posterior percutaneous pedicle screw fixation/reduction is a safe, reproducible, and effective technique for patients with symptomatic degenerative spondylolisthesis at the L4–5 vertebral segment.

Restricted access

Namath S. Hussain, David Hanscom and Rod J. Oskouian Jr.

Injury to the lymphatic channels is a rare and relatively unknown complication of anterior approaches to the lumbar spine and can cause fluid to build up in the retroperitoneal space, resulting in a lymphocele. If they enlarge sufficiently, these collections of chyle in the abdomen can cause pain and bowel ischemia, and can compress nearby organs. The authors report 4 cases in which anterior approaches to the lumbar spine were complicated by a postoperative retroperitoneal chylous fluid collection. They describe the anatomy of the lymphatic system and pathophysiology of this disease entity, review the sparse literature on this subject, and recommend a treatment algorithm. Maintaining a high index of suspicion for this clinical entity in patients who have recently undergone an anterior approach to the thoracic or lumbar spine is vital to avoid delays in diagnosis and treatment.

Restricted access

Jay Jagannathan, Chun-Po Yen, Dibyendu Kumar Ray, David Schlesinger, Rod J. Oskouian, Nader Pouratian, Mark E. Shaffrey, James Larner and Jason P. Sheehan

Object

This study evaluated the efficacy of postoperative Gamma Knife surgery (GKS) to the tumor cavity following gross-total resection of a brain metastasis.

Methods

A retrospective review was conducted of 700 patients who were treated for brain metastases using GKS. Forty-seven patients with pathologically confirmed metastatic disease underwent GKS to the postoperative resection cavity following gross-total resection of the tumor. Patients who underwent subtotal resection or who had visible tumor in the resection cavity on the postresection neuroimaging study (either CT or MR imaging with and without contrast administration) were excluded. Radiographic and clinical follow-up was assessed using clinic visits and MR imaging. The radiographic end point was defined as tumor growth control (no tumor growth regarding the resection cavity, and stable or decreasing tumor size for the other metastatic targets). Clinical end points were defined as functional status (assessed prospectively using the Karnofsky Performance Scale) and survival. Primary tumor pathology was consistent with lung cancer in 19 cases (40%), melanoma in 10 cases (21%), renal cell carcinoma in 7 cases (15%), breast cancer in 7 cases (15%), and gastrointestinal malignancies in 4 cases (9%). The mean duration between resection and radiosurgery was 15 days (range 2–115 days). The mean volume of the treated cavity was 10.5 cm3 (range 1.75–35.45 cm3), and the mean dose to the cavity margin was 19 Gy. In addition to the resection cavity, 34 patients (72%) underwent GKS for 116 synchronous metastases observed at the time of the initial radiosurgery.

Results

The mean radiographic follow-up duration was 14 months (median 10 months, range 4–37 months). Local tumor control at the site of the surgical cavity was achieved in 44 patients (94%), and tumor recurrence at the surgical site was statistically related to the volume of the surgical cavity (p = 0.04). During follow-up, 34 patients (72%) underwent additional radiosurgery for 140 new (metachronous) metastases. At the most recent follow-up evaluation, 11 patients (23%) were alive, whereas 36 patients had died (mean duration until death 12 months, median 10 months). Patients who showed good systemic control of their primary tumor tended to have longer survival durations than those who did not (p = 0.004). At the last clinical follow-up evaluation, the mean Karnofsky Performance Scale score for the overall group was 78 (median 80, range 40–100).

Conclusion:

Radiosurgery appears to be effective in terms of providing local tumor control at the resection cavity following resection of a brain metastasis, and in the treatment of synchronous and metachronous tumors. These data suggest that radiosurgery can be used to prevent recurrence following gross-total resection of a brain metastasis.

Restricted access

Jay Jagannathan, Christopher I. Shaffrey, Rod J. Oskouian, Aaron S. Dumont, Christian Herrold, Charles A. Sansur and John A. Jane Sr.

Object

Although the clinical outcomes following anterior cervical discectomy and fusion (ACDF) surgery are generally good, 2 major complications are graft migration and nonunion. These complications have led some to advocate rigid internal fixation and/or cervical immobilization postoperatively. This paper examines a single-surgeon experience with single-level ACDF without use of plates or hard collars in patients with degenerative spondylosis in whom allograft was used as the fusion material.

Methods

The authors conducted a retrospective review of a prospective database of (Cloward-type) ACDF operations performed by the senior author (J.A.J.) between July 1996 and June 2005. Radiographic follow-up included static and flexion/extension radiographs obtained to assess fusion, focal and segmental kyphosis, and change in disc space height. At most recent follow-up, the patients' condition was evaluated by an independent physician examiner. The Odom criteria and Neck Disability Index (NDI) were used to assess outcome.

Results

One hundred seventy patients underwent single-level ACDF for degenerative pathology during the study period. Their most common presenting symptoms were pain, weakness, and radiculopathy; 88% of patients noted ≥ 2 neurological complaints. The mean hospital stay was 1.76 days (range 0–36 days), and 3 patients (2%) had major immediate postoperative complications requiring reoperation. The mean duration of follow-up was 22 months (range 12–124 months). Radiographic evidence of fusion was present in 160 patients (94%). Seven patients (4%) showed radiographic evidence of pseudarthrosis, and graft migration was seen in 3 patients (2%). All patients had increases in focal kyphosis at the operated level on postoperative radiographs (mean −7.4°), although segmental alignment was preserved in 133 patients (78%). Mean change in disc space height was 36.5% (range 28–53%). At most recent clinical follow-up, 122 patients (72%) had no complaints referable to cervical disease and were able to carry out their activities of daily living without impairment. The mean postoperative NDI score was 3.2 (median 3, range 0–31).

Conclusions

Single-level ACDF without intraoperative plate placement or the use of a postoperative collar is an effective treatment for cervical spondylosis. Although there is evidence of focal kyphosis and loss of disc space height, radiographic evidence of fusion is comparable to that attained with plate fixation, and the rate of clinical improvement is high.

Restricted access

Jason Sheehan, Adina Ionescu, Nader Pouratian, D. Kojo Hamilton, David Schlesinger, Rod J. Oskouian Jr. and Charles Sansur

Object

Adjuvant treatment with radiation (radiation therapy or radiosurgery) is a mainstay of treatment for patients harboring glioblastomas multiforme (GBM). Hypoxic regions within the tumor make cells less sensitive to radiation therapy. Trans sodium crocetinate (TSC) has been shown to increase oxygen diffusion in the brain and elevate the partial brain oxygen level. The goal of this study was to evaluate the radiosensitizing effects of TSC on GBM tumors.

Methods

A rat C6 glioma model was used, in which C6 glioma cells were stereotactically injected into the rat brain to create a tumor. Following creation of a right frontal tumor, animals were randomized into 1 of 4 groups: 1) TSC alone (animal treated with moderate-dose TSC only); 2) radiation (animals receiving 8 Gy of cranial radiation); 3) radiation and low-dose TSC (animals receiving 8 Gy of radiation and 50 μg/kg of TSC); or 4) radiation and moderate-dose TSC (animals receiving 8 Gy of radiation and 100 μg/kg of TSC). Animals were observed clinically for 60 days or until death. Magnetic resonance (MR) imaging was performed at 2-week intervals on each animal and quantitatively evaluated for tumor response. Immunohistochemical analysis was performed on all brain tumors. Survival differences were also evaluated using the Kaplan–Meier method.

Results

On MR imaging, a statistically significant reduction in tumor size was seen in the group receiving moderate-dose TSC and radiation treatment compared with the group receiving radiation treatment alone. The rate of tumor growth was significantly less for the combination of TSC and radiation treatment compared with either modality alone. Median survival times for the TSC-only and the radiation therapy–only groups were 15 and 30 days, respectively. The 60-day median survival times for the groups receiving a combination of either low- or moderate-dose TSC with radiation therapy were statistically improved compared with those for the other treatment groups.

Conclusions

Use of TSC improves the extent of GBM tumor regression following radiation therapy and enhances survival. Radiosensitization of hypoxic tumors through increased oxygen diffusion may have clinical utility in patients with GBM tumors but must be explored in a clinical trial.

Full access

Charles A. Sansur, Kai-Ming G. Fu, Rod J. Oskouian Jr., Jay Jagannathan, Charles Kuntz iv and Christopher I. Shaffrey

✓ Ankylosing spondylitis (AS) is an inflammatory rheumatic disease whose primary effect is on the axial skeleton, causing sagittal-plane deformity at both the thoracolumbar and cervicothoracic junctions. In the present review article the authors discuss current concepts in the preoperative planning of patients with AS. The authors also review current techniques used to treat sagittal-plane deformity, focusing on pedicle subtraction osteotomy at the thoracolumbar junction, as well as cervical extension osteotomy at the cervicothoracic junction.