Contralateral approach using microscope and tubular retractor system for ipsilateral decompression of lumbar degenerative lateral recess stenosis associated with narrow spinal canal

Objective

To summarize the clinical effect of a single-center retrospective analysis of the contralateral approach with a microscope and tubular retractor system for ipsilateral decompression in patients with lumbar lateral recess stenosis and a narrow spinal canal.

Methods

A total of 25 patients who underwent ipsilateral decompression surgery via a contralateral approach with microscope and tubular retractor system, performed by one surgeon at a single center were retrospectively examined. The width of the lamina fenestration was compared with the preoperative distance from the root of the spinous process to the dorsal articular facet, the bilateral articular facet change in the suprapedicle notch section on CT scan, and with the changes in transverse and sagittal diameters of the canal area on MRI. Clinical efficacy was assessed using the Japanese Orthopedic Association (JOA), Visual Analog Scale (VAS), and Oswestry Disability Index (ODI) scores.

Results

In total, 25 patients were treated and the mean intraoperative time was 82.04 ± 12.48 min. There was no nerve injury, cerebrospinal fluid leakage, and infection complications. The postoperative CT revealed that the width of the contralateral laminar fenestration was less than the distance from the root of the spinous process to the dorsal articular facet. The residual widths of the ipsilateral articular facet and contralateral articular facet were greater than 2/3 of the preoperative articular facet width. The transverse and sagittal diameter of canal were significantly increased. The mean follow-up period was 12-16 months, and no recurrence or reoperation incidence were found at the last follow-up. When compared to pre-surgery, the ODI, VAS, and JOA scores were significantly improved after surgery (p < 0.05).

Conclusion

Based on our single-center retrospective observation of 25 cases and combined with previous literature, the contralateral approach with a microscope and tubular retractor system for ipsilateral decompression in patients with lumbar lateral recess stenosis and a narrow spinal canal can reduce damage to the articular processes, and probably more conducive to the postoperative stability of the lumbar spine. This was a single center retrospective analysis with a small sample size and lacked randomized controlled trials (RCTs). However, larger-scale, multicenter RTCs are required for additional validation.

[Imaging study and clinical application of unilateral biportal endoscopy technique for upper lumbar disc herniation via contralateral approach]

Objective

To investigate the relationships between the bony structures, nerve, and indentations of ligamentum flavum of the upper lumbar spine by using CT three-dimensional reconstruction technique, in order to guide the unilateral biportal endoscopy (UBE) technique via contralateral approach in the treatment of upper lumbar disc herniation (ULDH).

Methods

Twenty-one ULDH patients who were admitted between June 2019 and July 2021 and met the selection criteria were selected as the research subjects. There were 12 males and 9 females with an average age of 62.1 years (range, 55-72 years). The disease duration was 1-12 years (mean, 5.7 years). There was 1 case of L 1, 2, 4 cases of L 2, 3, and 16 cases of L 3, 4. The CT myelography data of T 12-S 3 segment was saved in DICOM format and imported into Mimics21.0 software for three-dimensional reconstruction. The relationship between the intersection (point Q) of spinous process and the inferior margin of lamina, the indentation of superior margin of ligamentum flavum, the inferior margin of nerve root origin, intervertebral space, and foramen were observed. The Mimics21.0 software was used to create a 3-mm-diameter cylinder to simulate the UBE channel and measure its abduction angle (∠b1), as well as measure the following lumbar vertebra-related indicators: in L 1,2-L 3,4 segments, the vertical distance from the point Q to the inferior margin of the contralateral lumbar pedicle of the same lumbar vertebra (a1), the superior margin of the contralateral pedicle of the lower lumbar vertebra (a2), the lower endplate of the same lumbar vertebra (a3), the upper endplate of the lower lumbar vertebra (a4); the vertical distance from the lower endplate of lumbar vertebra to the inferior margin of the lumbar pedicle (c1), the vertical distance from the upper endplate of the lower lumbar vertebra to the superior margin of the lumbar pedicle (c2); the vertical distance from the inferior margin of the nerve root origin to the superior margin (d1) and the inferior margin (d2) of the lumbar pedicle, respectively; the vertical distance from the intersection (point P) of the indentation of superior margin of ligamentum flavum and the medial margin of the lumbar pedicle to the superior margin (e1) and the inferior margin (e2) of the lumbar pedicle, respectively; the horizontal distance from the lateral margin of the dural mater (f1) and the narrowest part of the lumbar isthmus (f2) to the facet joint space, respectively. Thirteen of the patients included in the study chose the UBE surgery via contralateral approach. There were 8 males and 5 females with an average age of 63.3 years (range, 55-71 years). The disease duration was 2-12 years, with an average of 6.2 years. There were 3 cases of L 2, 3 and 10 cases of L 3, 4. The perioperative complications and surgical decompression were recorded. And the effectiveness were evaluated by visual analogue scale (VAS) score, Oswestry disability index (ODI), and short form-36 health survey (SF-36) score.

Results

The imaging results showed that there was no significant difference in a1, a3, a4, e1, e2, f1, and f2 between segments ( P>0.05), and there were significant differences ( P<0.05) in a2 and c2 between L 1, 2 and L 3, 4 segments, in ∠b1 and d2 between L 1, 2, L 2, 3 segments and L 3, 4 segments, and in c1 and d1 between L 1, 2 and L 2, 3, L 3, 4 segments. The 87.30% (110/126) of point Q of L 1, 2-L 3, 4 segments corresponded to the inferior articular process, and 78.57% (99/126) of the lower endplate corresponded to the level of the isthmus. All 13 patients completed the UBE surgery via contralateral approach, and none were converted to open surgery. All patients were followed up 12-17 months (mean, 14.6) months. The VAS score of low back pain and leg pain, ODI, and SF-36 score at 6 and 12 months after operation significantly improved when compared with those before operation ( P<0.05), and further improved at 12 months after operation when compared with 6 months after operation ( P<0.05). The imaging review results showed that the herniated disc was removed and the dura mater was decompressed adequately.

Conclusion

The point Q, the superior margin of ligamentum flavum, and lumbar pedicle can be used as the markers for the treatment of ULBD with UBE surgery via contralateral approach, making the procedure safer, more precise, and more effective.

Contralateral interoptic approach to paraclinoid aneurysms: a patient-selection algorithm based on anatomical investigation and clinical validation

OBJECTIVE

Aneurysms that arise on the medial surface of the paraclinoid segment of the internal carotid artery (ICA) are surgically challenging. The contralateral interoptic trajectory, which uses the space between the optic nerves, can partially expose the medial surface of the paraclinoid ICA. In this study, the authors quantitatively measure the area of the medial ICA accessible through the interoptic triangle and propose a potential patient-selection algorithm that is based on preoperative measurements on angiographic imaging.

METHODS

The contralateral interoptic trajectory was studied on 10 sides of 5 cadaveric heads, through which the medial paraclinoid ICA was identified. The falciform ligament medial to the contralateral optic canal was incised, the contralateral optic nerve was gently elevated, and the medial surface of the paraclinoid ICA was inspected via different viewing angles to obtain maximal exposure. The accessible area on the carotid artery was outlined. The distance from the distal dural ring (DDR) to the proximal and distal borders of this accessible area was measured. The superior and inferior borders were measured using the clockface method relative to a vertical line on the coronal plane. To validate these parameters, preoperative measurements and intraoperative findings were reviewed in 8 clinical cases.

RESULTS

In the sagittal plane, the mean (SD) distances from the DDR to the proximal and distal ends of the accessible area on the paraclinoid ICA were 2.5 (1.52) mm and 8.4 (2.32) mm, respectively. In the coronal plane, the mean (SD) angles of the superior and inferior ends of the accessible area relative to a vertical line were 21.7° (14.84°) and 130.9° (12.75°), respectively. Six (75%) of 8 clinical cases were consistent with the proposed patient-selection algorithm.

CONCLUSIONS

The contralateral interoptic approach is a feasible route to access aneurysms that arise from the medial paraclinoid ICA. An aneurysm can be safely clipped via the contralateral interoptic trajectory if 1) both proximal and distal borders of the aneurysm neck are 2.5-8.4 mm distal to the DDR, and 2) at least one border of the aneurysm neck on the coronal clockface is 21.7°-130.9° medial to the vertical line.

Quantitative analysis of ipsilateral and contralateral supracerebellar infratentorial and occipital transtentorial approaches to the cisternal pulvinar: laboratory anatomical investigation

OBJECTIVE

The cisternal pulvinar is a challenging location for neurosurgery. Four approaches for reaching the pulvinar without cortical transgression are the ipsilateral supracerebellar infratentorial (iSCIT), contralateral supracerebellar infratentorial (cSCIT), ipsilateral occipital transtentorial (iOCTT), and contralateral occipital transtentorial/falcine (cOCTF) approaches. This study quantitatively compared these approaches in terms of surgical exposure and maneuverability.

METHODS

Each of the 4 approaches was performed in 4 cadaveric heads (8 specimens in total). A 6-sided anatomical polygonal region was configured over the cisternal pulvinar, defined by 6 reachable anatomical points in different vectors. Multiple polygons were subsequently formed to calculate the areas of exposure. The surgical freedom of each approach was calculated as the maximum allowable working area at the proximal end of a probe, with the distal end fixed at the posterior pole of the pulvinar. Areas of exposure, surgical freedom, and the working distance (surgical depth) of all approaches were compared.

RESULTS

No significant difference was found among the 4 different approaches with regard to the surgical depth, surgical freedom, or medial exposure area of the pulvinar. In the pairwise comparison, the cSCIT approach provided a significantly larger lateral exposure (39 ± 9.8 mm2) than iSCIT (19 ± 10.3 mm2, p < 0.01), iOCTT (19 ± 8.2 mm2, p < 0.01), and cOCTF (28 ± 7.3 mm2, p = 0.02) approaches. The total exposure area with a cSCIT approach (75 ± 23.1 mm2) was significantly larger than with iOCTT (43 ± 16.4 mm2, p < 0.01) and iSCIT (40 ± 20.2 mm2, p = 0.01) approaches (pairwise, p ≤ 0.01).

CONCLUSIONS

The cSCIT approach is preferable among the 4 compared approaches, demonstrating better exposure to the cisternal pulvinar than ipsilateral approaches and a larger lateral exposure than the cOCTF approach. Both contralateral approaches described (cSCIT and cOCTF) provided enhanced lateral exposure to the pulvinar, while the cOCTF provided a larger exposure to the lateral portion of the pulvinar than the iOCTT. Medial exposure and maneuverability did not differ among the approaches. A short tentorium may negatively impact an ipsilateral approach because the cingulate isthmus and parahippocampal gyrus tend to protrude, in which case they can obstruct access to the cisternal pulvinar ipsilaterally.

Contralateral Eyebrow Approach for Unilateral Suprasellar Meningioma

Unilateral suprasellar meningiomas have distinct features compared to other midline tumors, as they may produce severe visual symptoms even if small due to an early involvement of the optic canal. Surgical treatment of these tumors from an ipsilateral approach is challenging, as the tumor is covered by the optic nerve that needs to be mobilized to access the optic canal extension. A contralateral approach allows a direct line of sight to the tumor despite a longer working distance. We report the case of a 49-year-old patient presenting with unilateral visual loss related to a left suprasellar meningioma extending to the left optic canal and displacing the optic nerve laterally. Through a right eyebrow approach, a 2.5/2 cm supraorbital bone flap was raised and the orbital floor was thoroughly flattened. After dural opening, the carotid cistern was opened and CSF evacuated allowing a surgery without fixed retractors. The intracranial part of the tumor was removed, but the optic nerve seemed to be still displaced by the intracanalicular part. Under copious irrigation, the medial part of the optic canal was drilled, the dura incised, and the tumor removed. Postoperative course was favorable and the patient made a complete visual recovery. Postoperative MRI showed complete removal of the tumor. We present different surgical steps and discuss the nuances of the procedure. The contralateral eyebrow approach is an interesting addition to the surgical armamentarium and should be discussed for unilateral suprasellar tumors.

The link to the video can be found at: https://youtu.be/2LTEOaGoKzo .

Up-and-Over Technique for Implantation of Iliac Branch Devices After Prior Aortic Endograft Repair

PURPOSE

To describe a modified up-and-over access technique for treatment of iliac artery aneurysms in patients with prior bifurcated stent-grafts for endovascular aneurysm repair (EVAR).

TECHNIQUE

This technique uses a coaxial 12-F flexible sheath that is docked with a through-and-through wire into a 7-F sheath advanced from the contralateral femoral approach. This maneuver allows both sheaths to be moved as a unit while maintaining position of the apex of the system as it loops over the flow divider, avoiding damage to or displacing the extant endograft. Once the 12-F sheath is positioned in the iliac limb of the aortic stent-graft and secured in place with the through-and-through wire, the repair is extended into the internal iliac artery using a bridging stent-graft or covered stent introduced via a coaxial sheath.

CONCLUSION

The up-and-over technique with a flexible 12-F sheath mated with a 7-F sheath from the opposite side allows bilateral femoral access to be used for iliac branch device placement after prior aortic endograft procedures that create a higher, acutely angled bifurcation. Use of a through-and-through wire and a coaxial sheath for stent delivery creates a very stable platform for intervention.

Contralateral approach for clipping of bilateral anterior circulation aneurysms

Patients with bilateral anterior circulation aneurysms present a management challenge. These lesions may be treated in a staged manner or alternatively, for select patients, a contralateral approach may be utilized to treat bilateral aneurysms with a single surgery. In this narrated video illustration, we present the case of a 57-year-old woman with incidentally discovered bilateral aneurysms (left middle cerebral artery [MCA], left anterior choroidal artery and right MCA). A contralateral approach through a left pterional craniotomy was performed formicrosurgical clipping of all three aneurysms. The techniques of pterional craniotomy, contralateral approach, microsurgical clipping and intraoperative angiography are reviewed. The authors are grateful to Wuyang Yang, M.D. for his assistance. The video can be found here: http://youtu.be/MlPIu3hQZkg.