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Navigated Transtubular Extraforaminal Decompression of the L5 Nerve Root at the Lumbosacral Junction: Clinical Data, Radiographic Features, and Outcome Analysis.

Stavrinou P, Härtl R, Krischek B, Kabbasch C, Mpotsaris A, Goldbrunner R - Biomed Res Int (2016)

Bottom Line: There was a significant improvement from preoperative to postoperative NRS with the results being sustainable at follow-up.ODI was also significantly improved after surgery.Conclusions.

View Article: PubMed Central - PubMed

Affiliation: Department of Neurosurgery, University Hospital of Cologne, 50937 Cologne, Germany.

ABSTRACT
Purpose. Extraforaminal decompression of the L5 nerve root remains a challenge due to anatomic constraints, severe level-degeneration, and variable anatomy. The purpose of this study is to introduce the use of navigation for transmuscular transtubular decompression at the L5/S1 level and report on radiological features and clinical outcome. Methods. Ten patients who underwent a navigation-assisted extraforaminal decompression of the L5 nerve root were retrospectively analyzed. Results. Six patients had an extraforaminal herniated disc and four had a foraminal stenosis. The distance between the L5 transverse process and the para-articular notch of the sacrum was 12.1 mm in patients with a herniated disc and 8.1 mm in those with a foraminal stenosis. One patient had an early recurrence and another developed dysesthesia that resolved after 3 months. There was a significant improvement from preoperative to postoperative NRS with the results being sustainable at follow-up. ODI was also significantly improved after surgery. According to the Macnab grading scale, excellent or good outcomes were obtained in 8 patients and fair ones in 2. Conclusions. The navigated transmuscular transtubular approach to the lumbosacral junction allows for optimal placement of the retractor and excellent orientation particularly for foraminal stenosis or in cases of complex anatomy.

No MeSH data available.


Related in: MedlinePlus

Axial T2-weighted MRI reveals extraforaminal ruptured disc on the left side (patient number 5). Therapy consists of removal of the fragmented disc segment without bone removal or discectomy. Navigation allows for a safe transmuscular approach.
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fig2: Axial T2-weighted MRI reveals extraforaminal ruptured disc on the left side (patient number 5). Therapy consists of removal of the fragmented disc segment without bone removal or discectomy. Navigation allows for a safe transmuscular approach.

Mentions: After induction of general anesthesia, patients were positioned prone on the carbon operating table with chest and pelvic bolsters. In lateral view, a 3 mm spinal process screw (25 mm length) was inserted in percutaneous fashion in the spinal process of L4 for fixation of the reference array. Using a Ziehm Vario 3D C-Arm (Ziehm Imaging GmbH, Germany), a 3D scan of the patient was acquired and the data set was transferred automatically to the navigation system. Using the Brainlab pointer and a virtual tip offset of variable length, the entry point and surgical trajectory were identified. A paramedian incision was made through the skin and fascia and, with the pointer as a guide, the initial dilator was passed through the paraspinal muscles until bone contact was made. After sequential dilation and insertion of the 19 mm dilator, the DePuy Insight Retractor was inserted and connected to the flex arm. At this point the position of the retractor was controlled with the navigation pointer and, if necessary, adjustments were made (Figure 1). Even before dissection of the soft tissue, the anatomic landmarks were identified with the pointer. The remnant soft tissue was removed under microscope until visualization of the lateral superior articular process of S1. Depending on the anatomical constrains in the individual patient, a drill was used to shave down the lateral facet and, if needed, the inferior margin of the L5 transverse process. Cranial angulation of the retractor as planned preoperatively helped to avoid the sacral ala in all cases. Further surgical strategy was adapted to the underlying pathology; in cases of a ruptured disc the nerve root was identified and retracted using a dissector, taking care not to injure the radicular vessels (Figure 2). The disc fragment was mobilized and removed with a hook followed by a conservative discectomy, meaning removal of disc material that may not be herniated yet but is in continuity with the herniated fragment or hanging loose in the intervertebral space. Removal of the whole disc material was not attempted. In cases of foraminal stenosis, the bony decompression is more important, and the drilling of the bony confines was more generous. After identification of the exiting nerve root, the osteophytes were also removed. Due to annular bulging, a discectomy was performed along the intra- and extraforaminal portion of the disc. At the end, the exploration along the nerve route up to the lumbosacral tunnel showed no signs of nerve impingement. Hemostasis was performed mainly with copious irrigation and bipolar cauterization as the retractor is slowly removed. No drainage was used and the wound was closed in standard fashion. Patients were mobilized on the first postoperative day.


Navigated Transtubular Extraforaminal Decompression of the L5 Nerve Root at the Lumbosacral Junction: Clinical Data, Radiographic Features, and Outcome Analysis.

Stavrinou P, Härtl R, Krischek B, Kabbasch C, Mpotsaris A, Goldbrunner R - Biomed Res Int (2016)

Axial T2-weighted MRI reveals extraforaminal ruptured disc on the left side (patient number 5). Therapy consists of removal of the fragmented disc segment without bone removal or discectomy. Navigation allows for a safe transmuscular approach.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4834392&req=5

fig2: Axial T2-weighted MRI reveals extraforaminal ruptured disc on the left side (patient number 5). Therapy consists of removal of the fragmented disc segment without bone removal or discectomy. Navigation allows for a safe transmuscular approach.
Mentions: After induction of general anesthesia, patients were positioned prone on the carbon operating table with chest and pelvic bolsters. In lateral view, a 3 mm spinal process screw (25 mm length) was inserted in percutaneous fashion in the spinal process of L4 for fixation of the reference array. Using a Ziehm Vario 3D C-Arm (Ziehm Imaging GmbH, Germany), a 3D scan of the patient was acquired and the data set was transferred automatically to the navigation system. Using the Brainlab pointer and a virtual tip offset of variable length, the entry point and surgical trajectory were identified. A paramedian incision was made through the skin and fascia and, with the pointer as a guide, the initial dilator was passed through the paraspinal muscles until bone contact was made. After sequential dilation and insertion of the 19 mm dilator, the DePuy Insight Retractor was inserted and connected to the flex arm. At this point the position of the retractor was controlled with the navigation pointer and, if necessary, adjustments were made (Figure 1). Even before dissection of the soft tissue, the anatomic landmarks were identified with the pointer. The remnant soft tissue was removed under microscope until visualization of the lateral superior articular process of S1. Depending on the anatomical constrains in the individual patient, a drill was used to shave down the lateral facet and, if needed, the inferior margin of the L5 transverse process. Cranial angulation of the retractor as planned preoperatively helped to avoid the sacral ala in all cases. Further surgical strategy was adapted to the underlying pathology; in cases of a ruptured disc the nerve root was identified and retracted using a dissector, taking care not to injure the radicular vessels (Figure 2). The disc fragment was mobilized and removed with a hook followed by a conservative discectomy, meaning removal of disc material that may not be herniated yet but is in continuity with the herniated fragment or hanging loose in the intervertebral space. Removal of the whole disc material was not attempted. In cases of foraminal stenosis, the bony decompression is more important, and the drilling of the bony confines was more generous. After identification of the exiting nerve root, the osteophytes were also removed. Due to annular bulging, a discectomy was performed along the intra- and extraforaminal portion of the disc. At the end, the exploration along the nerve route up to the lumbosacral tunnel showed no signs of nerve impingement. Hemostasis was performed mainly with copious irrigation and bipolar cauterization as the retractor is slowly removed. No drainage was used and the wound was closed in standard fashion. Patients were mobilized on the first postoperative day.

Bottom Line: There was a significant improvement from preoperative to postoperative NRS with the results being sustainable at follow-up.ODI was also significantly improved after surgery.Conclusions.

View Article: PubMed Central - PubMed

Affiliation: Department of Neurosurgery, University Hospital of Cologne, 50937 Cologne, Germany.

ABSTRACT
Purpose. Extraforaminal decompression of the L5 nerve root remains a challenge due to anatomic constraints, severe level-degeneration, and variable anatomy. The purpose of this study is to introduce the use of navigation for transmuscular transtubular decompression at the L5/S1 level and report on radiological features and clinical outcome. Methods. Ten patients who underwent a navigation-assisted extraforaminal decompression of the L5 nerve root were retrospectively analyzed. Results. Six patients had an extraforaminal herniated disc and four had a foraminal stenosis. The distance between the L5 transverse process and the para-articular notch of the sacrum was 12.1 mm in patients with a herniated disc and 8.1 mm in those with a foraminal stenosis. One patient had an early recurrence and another developed dysesthesia that resolved after 3 months. There was a significant improvement from preoperative to postoperative NRS with the results being sustainable at follow-up. ODI was also significantly improved after surgery. According to the Macnab grading scale, excellent or good outcomes were obtained in 8 patients and fair ones in 2. Conclusions. The navigated transmuscular transtubular approach to the lumbosacral junction allows for optimal placement of the retractor and excellent orientation particularly for foraminal stenosis or in cases of complex anatomy.

No MeSH data available.


Related in: MedlinePlus