Surgical treatment of intraforaminal/extraforaminal lumbar disc herniations: Many approaches for few surgical routes

New Axially Expandable Oblique Cage Designed for Anterior to Psoas (ATP) Approach: Indications-Surgical Technique and Clinical-Radiological Outcomes in Patients with Symptomatic Degenerative Disc Disease

Background: Standard oblique cages cannot cover endplates side-to-side, which is an important biomechanical factor for reducing the risk of cage subsidence and for restoring correct segmental lordosis. The aim of this study is to evaluate the radiological and clinical results of a new oblique lumbar interbody fusion (OLIF) axially expandable cage. Methods: This is a prospective observational case-control study. From March 2018 to June 2020, 28 consecutive patients with lumbar degenerative disease underwent an ATP approach, with the insertion of a new axially expandable cage, which was used as a stand-alone procedure or followed by posterior percutaneous pedicle fixation. Results: Twenty-eight patients in both groups met the inclusion criteria. The mean follow-up time was 31.2 months (range of 13-37). The clinical results were not significantly different, although in the control group, two major intraoperative complications were recorded, and slight improvements in ODI and SF-36 scores were observed in the study group. The radiological results showed a less frequent incidence of subsidence and a higher rate of fusion in the study group compared to controls. Conclusions: The axially expandable oblique cage for lumbar inter body fusion, specifically designed for the ATP approach, represents an innovation and a technical improvement. The insertion and the axial expansion technique are safe and easy. The large footprint could obtain solid and effective arthrodesis, potentially reducing the risk of subsidence.

Comparative Analysis on Surgical Operability and Degree of Exposure of Microsurgical Approaches to Intraforaminal Lumbar Disk Herniations

BACKGROUND

 Intraforaminal lumbar disk herniations (IFDHs) represent a heterogeneous and relatively uncommon disease; their treatment is technically demanding due to the anatomical relationships with nerve roots and vertebral joints. Over time, several approaches have been developed without reaching a consensus about the best treatment strategy.

MATERIALS AND METHODS

 Authors comparatively analyze surgical operability and exposure in terms of quantitative variables between the different microsurgical approaches to IFDHs, defining the impact of each approach on surgical maneuverability and exposure on specific targets.A comparative microanatomical laboratory investigation was conducted. The operability score (OS) was applied for quantitative analysis of surgical operability.

RESULTS

 Transarticular and combined translaminar-trans-pars-interarticularis approaches result in providing the best surgical exposure and maneuverability on all targets with surgical controls on both nerve roots, at the expense of a higher risk of iatrogenic instability. Trans-pars-interarticularis approach reaches comparable levels of operability, even limited to the pure foraminal area (lateral compartment); similar findings were recorded for partial facetectomy on the medial compartment. The contralateral interlaminar approach provides good visualization of the foramen without consensual favorable maneuverability, which should be considered the main drawback.

CONCLUSIONS

 Approach selection has to consider disease location, the possible migration of disk fragments, the degree of nerve root involvement, and risk of iatrogenic instability. According to the findings, authors propose an operative algorithm to tailor the surgical strategy, based both on the precise definition of anatomic boundaries of exposure of each approach and on surgical maneuverability on specific targets.

Recurrent or junctional lumbar foraminal herniated disc in patients operated with trans pars microscopic approach

This is a retrospective monocentric study. The aim of this study is to analyze the incidence of recurrent or junctional lumbar foraminal herniated disc, in patients treated with trans pars microsurgical approach. Foraminal lumbar disc herniation represents a challenging pathology for the spinal surgeon. The appropriate surgical approach still represents a matter of debate. Several open and minimally-invasive techniques have been developed, in order to allow a proper tissue exposure and preserving the vertebral stability. The trans pars approach has already been described as a possible alternative, allowing excellent exposure of the herniated fragment with minimum bone removal. While few studies have analyzed the very low rate of post-operative instability, no articles deal with the incidence of post-operative herniated disc recurrence or junctional disc herniation in patients treated with this technique. We enrolled 160 patients operated at our institution. A univariate and multivariate analysis of possible factors influencing outcome (age, sex, level and BMI) was performed. Outcome variables were recurrent or junctional herniated disc. At the end, 135 patients were analyzed. Of the 135 patients, six presented recurrent herniated disc (4.4%) and other three developed a junctional herniation (2.2%). The occurrence of junctional herniated disc or recurrent herniated disc was not influenced by the analyzed variables, both at univariate and at multivariate analyses. The trans pars approach presents a low rate of recurrence and junctional herniation. Age, sex, level, and BMI do not influence the recurrence rate, both at same level and at junctional level.

Transpars approach for L5-S1 foraminal and extra-foraminal lumbar disc herniations: technical note

BACKGROUND

The short pars and the narrowed surgical corridor for far lateral L5S1 herniation make the transpars approach challenging. The aim of this study is to determine the feasibility, efficacy, and safety of the transpars microscopic approach for the treatment of L5-S1 foraminal and extraforaminal lumbar disc herniation.

METHODS

From 2015 to 2019, patients with L5-S1 far lateral lumbar disc herniation were prospectively recruited. Drug intake, working days lost, NRS-leg, NRS-back, nerve-root palsy, Oswestry disability-index, Macnab criteria were recorded before surgery and at follow-up. Patients were seen at 1-6-12 months after surgery. Lumbar dynamic X-rays were performed at 6-12 months after surgery and again at 2-4 years after surgery. Key-steps of surgery are described.

RESULTS

Fourteen patients were enrolled. NRS-leg and NRS-back scores significantly improved (from 7.93 to 1.43 and from 3.2 to 0.6, respectively; P<0.0001). Oswestry Score significantly decreased (from 63.14 to 19.36 at 12 months; P<0.0001). L5 Root palsy improved in all cases (from 3.72/5 to 5/5; P<0.0001). At 12-months, excellent or good outcome (Macnab criteria) was achieved in 12 (85.7%) and 2 (14.3%) patients, respectively. All patients who were not retired returned to work within 30 days after surgery. No recurrence, instability or re-operations occurred.

CONCLUSIONS

The trans pars microscopic approach is feasible, safe, and effective for L5-S1 foraminal and extraforaminal disc herniation. During surgery, the key-point is the oblique working angle, directed caudally, parallel to L5 pedicle. The iliac crest does not seem to constitute an obstacle.

Percutaneous Endoscopic Discectomy Via a Transforaminal Approach for L5/S1 Far-Lateral Disc Herniation Assisted by Intraoperative Computed Tomography

OBJECTIVE

To examine the clinical outcomes of a percutaneous lumbar transforaminal endoscopic discectomy (PTED) with intraoperative computed tomography (iCT) navigation for the treatment of L5-S1 far-lateral lumbar disc herniation (LDH).

METHODS

A total of 30 patients with L5-S1 far-lateral LDH who underwent PTED with iCT navigation from September 2016 to October 2020 were enrolled in this study. Outcomes were assessed using the visual analog scale pain score, the Oswestry Disability Index, the Japanese Orthopedic Association score, the EQ-5D-5 L and the modified Macnab criteria. Preoperative and postoperative complications were recorded.

RESULTS

The mean visual analog scale score for leg pain improved from 8.1 at baseline to 2.3, 0.9, 0.7 and 0.9 at 1 day, 1 week, 6 months, and 12 months postoperatively, respectively (P < 0.01). The mean Oswestry Disability Index improved from 78.1% at baseline to 45.5%, 21.9%, 12.6%, and 11.7% at 1 week, 1 month, 6 months, and 12 months postoperatively, respectively (P < 0.01); and the mean Japanese Orthopedic Association score improved from 8.6 at baseline to 14.2, 20.2, 24.4, and 25.6 at 1 day, 1 week, 6 months, and 12 months postoperatively, respectively (P < 0.01). At 12 months postoperatively, the EQ-5D-5 L value significantly increased, from -0.061 ± 0.138 to 0.903 ± 0.064. The rate of a good or excellent modified Macnab result was 93% (26/28) at 12 months postoperatively. In the present study, combined L5-S1 foraminal stenosis tended to lead poor outcomes, which required more postsurgical treatments.

CONCLUSIONS

With iCT navigation, PTED is a feasible and effective minimally invasive surgery for L5-S1 far-lateral LDH.

A Modified Approach for Minimally Invasive Tubular Microdiscectomy for Far Lateral Disc Herniations: Docking at the Caudal Level Transverse Process

Background and Objectives: The use of minimally invasive retractor systems has significantly decreased the amount of tissue dissection and blood loss, and the duration of post-operative recovery after far-lateral disc herniations (FLDH). In this technical note, the technique of docking the tubular retractor on the caudal transverse process is described for an efficient approach with a decreased need for manipulation of the exiting nerve root. Materials and Methods: The case reported is that of a woman affected by a right-sided FLDH at the L4–5 level causing an L4 radiculopathy with weakness and numbness. A review of the literature for FLDH regarding the key anatomy used during a far lateral approach was also performed. Results: The patient showed a significant improvement of her dorsiflexion weakness and radiating leg pain at her 2-week and 5-week post-operative visits, and at a 6-month follow-up she had near-complete relief of her symptoms, including resolution of foot numbness. Prior techniques for tubular microdiscectomy for FLDH report docking on the facet joint, pars interarticularis, and the cranial transverse process. Conclusions: This technical note details that the utility of docking a tubular retractor at the caudal transverse process improves upon already established techniques for minimally invasive tubular discectomy for FLDH.

No Gender Differences in Pain Perception and Medication after Lumbar Spine Sequestrectomy—A Reanalysis of a Randomized Controlled Clinical Trial

Background: Gender issues have received increasing attention in clinical research of the past years, and biological sex has been introduced as a moderating variable in experimental pain perception. However, in clinical studies of acute pain and gender, there are conflicting results. In particular, there are limited data on the impact of gender differences after spinal sequestrectomy. The aim of this work is to examine gender differences in postoperative pain and pain medication consumption in an inpatient clinical setting. Methods: Data of a completed double-blind RCT was subdivided by gender and reanalyzed by means of an analysis of variance in repeated measures. Outcomes included pain severity measured on a VAS, affective (SES-A) and sensory pain perception (SES-S) and morphine equivalent doses (MED) of analgesics after spinal sequestrectomy. Results: In total, 42 female (47.73%) and 46 male (52.27%) patients were analyzed. No differences in pain severity (VAS: Gender × Time F = 0.35; (df = 2, 86); p = 0.708), affective and sensory pain perception (SES-A: Gender × Time F = 0.08; (df = 2, 86); p = 0.919; SES-S: Gender × Time F = 0.06; (df = 2, 86); p = 0.939) or post-operative opioid use between men and women (MEDs: Gender × Time F = 1.44; (df = 2, 86); p = 0.227) could be observed. Conclusions: This reanalysis of an RCT with respect to gender differences is to our knowledge the first attempt to investigate the role of gender in pain perception and medication after lumbar spine sequestrectomy. In contrast to other studies, we were not able to show significant differences between male and female patients in all pain-related outcomes. Apart from well-established pain management, psychological reasons such as gender-specific response biases or the observer effect might explain our results. Trial registration: The study was registered as a regulatory phase IV study at the German Clinical Trials Register (DRKS), an open-access online register for clinical trials conducted in Germany (Reg-No: DRKS00007913).

Ultrasound Lancet-aided Translaminar Posterior Lumbar Approach to the Recesso-Foraminal Area: Technical Note

Extrusion and sequestration of the nucleus pulposus involving the spinal canal or the foramina/recesses complicates up to 28% of the lumbar disc herniations. The transpars/translaminar anatomical approach is well described and its advantages when handling with a lateral, foraminal extruded disc herniation are appreciated and recognized. Nevertheless, this approach presents several pitfalls such as the risk of disconnecting the pars interarticularis, which may cause segmental instability. This particular eventuality is because of the particular anatomical conformation of the pars interarticularis. Although already part of the modern surgical armamentarium for general, orthopedic, cranial and spinal surgeons, the use of the ultrasonic scalpel technique for such approach has never been discussed to date, to the best of our knowledge. The purpose of the present paper is therefore to introduce and describe the stepwise technique along with an extensive discussion of the facilitating role of the ultrasonic scalpel in the translaminar/transpars approach in the management of extruded disc herniation of the lumbar spine.

Could isthmic approach to far lateral disc hernias cause instability?

BACKGROUND

The aim of this study is to investigate the relationship between the degree of instability and the amount of isthmus excised during transpars (isthmic) approach which is accomplished with partial resection of the pars interarticularis used in distal lateral disc herniation.

METHODS

Thirty-six ovine lumbar spine segments were used in the study. 25% and 50% of the right side isthmus of each spinal segment were excised. Flexion, lateral bending and axial rotation tests were performed in both groups.

FINDINGS

There was no statistically significant difference found between the groups for yield moment, stiffness and ultimate load in flexion tests (p = 0.262, p = 0.749 and p = 0.200, respectively). Statistically significant difference was found between the groups for yield moment, stiffness and maximum load in lateral bending tests (p = 0.016, p = 0.010 and p = 0.016, respectively). There was no statistical difference found between the groups for yield torque and stiffness in axial rotation tests (p = 0.855 and p = 0.314).

INTERPRETATION

These results show that a significant loss of resistance especially during the lateral bending loading was occurred with increasing resection portion of isthmus. With the load applied during the lateral bending of the pars interarticularis, the vertebra resected by 50% percent fractured significantly easier in comparison to the vertebra resected by 25% percent. Pars interarticularis is an important structure with an important role in stability. It is presumed that the more defect is created during the drill-up of the pars interarticularis, the more instability will be occurred.