Radiographic comparison of L5–S1 lateral anterior lumbar interbody fusion cage subsidence and displacement by fixation strategy: anterior plate versus integrated screws

J Neurosurg Spine 38:126–130, 2023

OBJECTIVE The aim of this study was to radiographically compare cage subsidence and displacement between L5–S1 lateral anterior lumbar interbody fusion (ALIF) cages secured with an anterior buttress plate and cages secured with integrated screws.

METHODS Consecutive patients who underwent L5–S1 lateral ALIF with supplemental posterior fixation by a single surgeon from June 2016 to January 2021 were reviewed. Radiographs were analyzed and compared between the two groups based on the type of fixation used to secure the L5–S1 lateral ALIF cage: 1) anterior buttress plate or 2) integrated screws. The following measurements at L5–S1 were analyzed on radiographs obtained preoperatively, before discharge, and at latest follow-up: 1) anterior disc height, 2) posterior disc height, and 3) segmental lordosis. Cage subsidence and anterior cage displacement were determined radiographically.

RESULTS One hundred thirty-nine patients (mean age 60.0 ± 14.3 years) were included for analysis. Sixty-eight patients were treated with an anterior buttress plate (mean follow-up 12 ± 5 months), and 71 were treated with integrated screws (mean follow-up 9 ± 3 months). Mean age, sex distribution, preoperative L5–S1 lordosis, preoperative L5–S1 anterior disc height, and preoperative L5–S1 posterior disc height were statistically similar between the two groups. After surgery, the segmental L5–S1 lordosis and L5–S1 anterior disc heights significantly improved for both groups, and each respective measurement was similar between the groups at final follow-up. Posterior disc heights significantly increased after surgery with integrated screws but not with the anterior buttress plate. As such, posterior disc heights were significantly greater at final follow-up for integrated screws. Compared with patients who received integrated screws, significantly more patients who received the anterior buttress plate had cage subsidence cranially through the L5 endplate (20.6% vs 2.8%, p < 0.01), cage subsidence caudally through the S1 endplate (27.9% vs 0%, p < 0.01), and anterior cage displacement (22.1% vs 0%, p < 0.01).

CONCLUSIONS In this radiographic analysis of 139 patients who underwent lateral L5–S1 ALIF supplemented by posterior fixation, L5–S1 cages secured with an anterior buttress plate demonstrated significantly higher rates of cage subsidence and anterior cage displacement compared with cages secured with integrated screws. While the more durable stability afforded by cages secured with integrated screws suggests that they may be a more viable fixation strategy for L5–S1 lateral ALIFs, there are multiple factors that can contribute to cage subsidence, and, thus, definitive presumption cannot be made that the findings of this study are directly related to the buttress plate.

A novel endoscope-assisted technique for lateral lumbar interbody fusion

J Neurosurg Spine 35:292–298, 2021

The lateral approach to the spine is generally well tolerated, but reports of debilitating injury to the lumbar plexus, iliac vessels, ureter, and abdominal viscera are increasingly recognized, likely related to the lack of direct visualization of these nearby structures. To minimize this complication profile, the authors describe here a novel, minimally invasive, endoscope-assisted technique for the LLIF and evaluate its clinical feasibility.

Seven consecutive endoscope-assisted lateral lumbar interbody fusion (LLIF) procedures by the senior authors were reviewed for the incidence of approachrelated complications. One patient had a postoperative approach-related complication. This patient developed transient ipsilateral thigh hip flexion weakness that resolved spontaneously by the 3-month follow-up. No patient experienced visceral, urological, or vascular injury, and no patient sustained a permanent neurological injury related to the procedure.

The authors’ preliminary experience suggests that this endoscope-assisted LLIF technique may be clinically feasible to mitigate vascular, urological, and visceral injury, especially in patients with previous abdominal surgery, anomalous anatomy, and revision operations. It provides direct visualization of at-risk structures without significant additional operative time. A larger series is needed to determine whether it reduces the incidence of lumbar plexopathy or visceral injury compared with traditional lateral approaches.

The lateral infratrigeminal transpontine window to deep pontine lesions

The lateral infratrigeminal transpontine window to deep pontine lesions

J Neurosurg 123:699–710, 2015

Surgery of brainstem lesions is increasingly performed despite the fact that surgical indications and techniques continue to be debated. The deep pons, in particular, continues to be a critical area in which the specific risks related to different surgical strategies continue to be examined. With the intention of bringing new knowledge into this important arena, the authors systematically examined the results of brainstem surgeries that have been performed through the lateral infratrigeminal transpontine window.

Methods Between 1990 and 2013, 29 consecutive patients underwent surgery through this window for either biopsy sampling or for removal of a deep pontine lesion. All of this work was performed at the Department of Neurosurgery of the Istituto Nazionale Neurologico “Carlo Besta”, in Milan, Italy. A retrospective analysis of the findings was conducted with the intention of bringing further clarity to this important surgical strategy.

Results The lateral infratrigeminal transpontine window was exposed through 4 different approaches: 1) classic retrosigmoid (15 cases), 2) minimally invasive keyhole retrosigmoid (10 cases), 3) translabyrinthine (1 case), and 4) combined petrosal (3 cases). No deaths occurred during the entire clinical study. The surgical complications that were observed included hydrocephalus (2 cases) and CSF leakage (1 case). In 6 (20.7%) of 29 patients the authors encountered new neurological deficits during the immediate postoperative period. All 6 of these patients had undergone lesion removal. In only 2 of these 6 patients were permanent sequelae observed at 3 months follow-up. These findings show that 93% of the patients studied did not report any permanent worsening of their neurological condition after this surgical intervention.

Conclusions This retrospective study supports the idea that the lateral infratrigeminal transpontine window is both a low-risk and safe corridor for either biopsy sampling or for removal of deep pontine lesions.

Surgical treatment of thoracic disc disease via minimally invasive lateral transthoracic trans/retropleural approach

Surgical treatment of thoracic disc disease via minimally

Neurosurg Rev (2013) 36:455–465

Thoracic disc herniations are associated with serious neurological consequences if not treated appropriately. Although a number of techniques have been described, there is no consensus about the best surgical approach. In this study, the authors report their experience in the operative management of patients with thoracic disc herniations using minimally invasive lateral transthoracic trans/retropleural approach.

A series of 33 consecutive patients with thoracic disc herniations who underwent anterior spinal cord decompression followed by instrumented fusion through lateral approach is being reported. Demographic and radiographic data, perioperative complications, and clinical outcomes were reviewed.

Forty disc levels in 33 patients (18F/15M; mean age, 52.9) were treated. Twenty-three patients presented with myelopathy (69 %), 31 had radiculopathy (94 %), and 31 had axial pain (94 %). Among patients with myelopathy, 14 (42.4 %) had bladder and/or bowel dysfunction. In the last eight cases (24 %), the approach was retropleural instead of transpleural. Patients were followed up for 18.2 months on average. The mean length of hospital stay was 5 days. None of the patients developed neurological deterioration postoperatively. Among 23 patients who had myelopathy signs, 21 (91 %) had improved postoperatively. The mean preoperative visual analog scale pain score, Oswestry Disability Index score, SF-36 PCS, and mental component summary scores were 7.5, 42.4, 29.6, and 37.5 which improved to 3.5, 33.2, 35.5, and 52.6, respectively. Perioperative complications occurred in six patients (18.1 %), all of which resolved uneventfully.

Minimally invasive lateral transthoracic trans/retropleural approach is a safe and efficacious technique for achieving adequate decompression in thoracic disc herniations in a less invasive manner than conventional approaches.

Surgical management of ventral and ventrolateral foramen magnum meningiomas

Neurosurg Rev (2012) 35:359–368

Foramen magnum meningioma poses a challenge for neurosurgeons. Prognosis has generally improved with diagnostic and surgical advances over the past two decades; however, it may ultimately depend more on the surgeon’s ability to tailor the approach and interpret intraoperative risks in single cases.

The series comprised 64 patients operated on for ventral and ventrolateral foramen magnum meningioma. All patients underwent preoperative magnetic resonance imaging and received surgery via the dorsolateral route, rendering the series homogeneous in neuroradiological workup and surgical treatment. Particular to this series was that the majority of patients were of advanced age (n=29; age, >65 years), had serious functional impairment (n=30, Karnofski score <70), and large tumors (mean diameter, 3.5 cm).

Total tumor removal was achieved in 52 (81 %) patients; operative mortality was nil. Early outcome varied depending on difficulties encountered at surgery (cranial nerve position and type of involvement in particular) and type of preoperative dysfunction. Long-tract signs and cerebellar deficits improved in 74 and 77 % of cases, respectively, but only 27 % of cranial nerve deficits did so. Surgical complications most often involved the cranial nerves: cranial nerve impairment, especially of the 9th through the 12th cranial nerves, due to stretching or encasement was noted in 44 cases. At final outcome assessment, two thirds of the cranial nerve deficits cleared, and all but two patients returned to a normal productive life. One patient was reoperated on during the follow-up period.

Foramen magnum meningiomas behave like clival or spinal tumors depending on their prevalent extension. A dorsolateral approach tailored to tumor position and extension and meticulous surgical technique allow for definitive control of surgical complications. Scrupulous postoperative care may prevent dysphagia, a major persistent complication of surgery. Long-term observation of indolent tumor behavior at follow-up suggests that incomplete resection may be a viable surgical treatment option.

Lumbar total disc replacement from an extreme lateral approach: clinical experience with a minimum of 2 years’ follow-up

J Neurosurg Spine 14:38–45, 2011. (DOI: 10.3171/2010.9.SPINE09865)

Current lumbar total disc replacement (TDR) devices require an anterior approach for implantation. This approach has inherent limitations, including risks to abdominal structures and the need for resection of the anterior longitudinal ligament (ALL). Placement of a TDR device from a true lateral (extreme lateral interbody fusion [XLIF]) approach is thought to offer a less invasive option to access the disc space, preserving the stabilizing ligaments and avoiding scarring of anterior vasculature. In this study, the authors attempted to quantify the clinical and radiographic outcomes of a lateral approach to lumbar TDR from a prospective, single-center experience.

Methods. A TDR device designed for implantation through a true lateral, retroperitoneal, transpsoas approach (XLIF) was implanted in 36 patients with discography-confirmed 1- or 2-level degenerative disc disease. Clinical (pain and function) and radiographic (range of motion [ROM]) data were prospectively collected preoperatively, postoperatively, and serially for a minimum of 24 months’ follow-up.

Results. Thirty-six surgeries were performed in 16 men and 20 women (mean age 42.6 years). Surgeries included 15 single-level TDR procedures at L3–4 or L4–5, three 2-level TDR procedures spanning L3–4 and L4–5, and 18 hybrid procedures (anterior lumbar interbody fusion [ALIF]) at L5–S1 and TDR at L4–5 [17] or L3–4 [1]). Operative time averaged 130 minutes, with an average blood loss of 60 ml and no intraoperative complications. Postoperative radiographs showed good device placement. All patients were walking within 12 hours of surgery and all but 9 were discharged the next day (7 of 9 had hybrid TDR/ALIF procedures). Five patients (13.8%) had psoas weakness and 3 (8.3%) had anterior thigh numbness postoperatively, both resolving within 2 weeks. One patient (2.8%) demonstrated weakness of the leg ipsilateral to the approach side, which lasted through the 3-month visit but was resolved by the 6-month visit. One patient (2.8%) was found to have hypertrophy of the quadriceps contralateral to the approach side at the 12-month visit, which was resolved by the 2-year visit. Four patients (11%) had postoperative facet joint pain, all in hybrid cases. All patients were 2 years or more postsurgery as of this writing, although 3 were lost to follow-up between the 1- and 2-year visits. In 2 cases (5.6%), removal of the TDR device and revision to fusion were required due to unresolved pain. At 2 years’ follow-up, the average visual analog scale and Oswestry Disability Index scores had improved 69.6% and 61.4%, respectively, and ROM averaged 8.6°, well within physiological norms.

Conclusions. Long-term results of a laterally placed TDR device demonstrate maintenance of pain relief and functional improvement. The benefits of this technique—minimal morbidity, avoiding mobilization of the great vessels, preserving the ALL, biomechanically stable orientation, and broader revision options—suggest a promising new direction for TDR procedures.