Transpars Microscopic Approach for the Treatment of Purely Foraminal Herniated Lumbar Disc: A Clinical, Radiological, Two-center Study

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.

Extra-laminar microscopic-assisted percutaneous nucleotomy (EL-MAPN) for the treatment of foraminal lumbar disc prolapse, a modified minimally invasive approach

PURPOSE

In this work, a modification of the percutaneous surgical approach for removing the lumbar foraminal disc prolapse is introduced.

MATERIAL AND METHODS

A prospective study was performed. The indication for surgery was foraminal disc prolapse presenting with acute motor or persistent sensory radiculopathy. MRI and X-ray of the lumbar spine were performed. VAS and ODI were recorded. The operation was done under general anesthesia. A needle was inserted for level-localization using C-arm. A 1.5 cm para-median skin incision was performed. A gradual dilatation using trocars was followed by the insertion of a tubular system. Under direct vision using the operative microscope, the lateral edge of the lamina was identified. A small, hooked probe was inserted in the foramen, and its position was documented fluoroscopically. With the help of the microscope, the triad consisting of Pedicle, Nerve root, and Prolapse "PNP" was identified. The nerve root was mobilized, and the prolapsed disc was removed.

RESULTS

The study included 50 patients, 26 females, and 24 males. The mean follow-up was 18 months. The mean operative time was 65 min. The mean blood loss was 105 ml. The mean VAS improved from 7.8 ± 2.3 preoperatively to 0.8 ± 0.3 after one year (p = 0.001). Mean ODI improved from 28 ± 10.4 to 4 ± 2.3 after one year (p = 0.02). A recurrent disc occurred in 2 patients and was revised in the same technique.

CONCLUSION

EL-MAPN represents a minimally invasive approach for foraminal disc prolapse removal under direct visual control avoiding injury to the facet joint or pars interarticularis.

Trans-Tubular Translaminar Microscopic-Assisted Nucleotomy for Lumbar Disc Herniations in the Hidden Zone

STUDY DESIGN

A prospective cohort study in a high-flow spine center in Germany.

OBJECTIVES

This study aimed to evaluate clinical outcomes and complications of the trans-tubular translaminar microscopic-assisted percutaneous nucleotomy in cases of cranially migrated lumbar disc herniations (LDH).

METHODS

Between January 2013 and January 2018, 66 consecutive patients with cranio-laterally migrated LDH were operated upon. The following outcome measures were evaluated: (1) Visual Analog Scale (VAS) for leg and back pain; (2) Oswestry Disability Index (ODI) and Macnab´s criteria. All patients were operated upon with trans-tubular Translaminar Microscopic-assisted Percutaneous Nucleotomy (TL-MAPN). Perioperative radiographic and clinical evaluations were reported. The mean follow-up period was 32 months.

RESULTS

The mean age was 59 years. L4/L5 was the commonest affected level (27 patients). The mean preoperative VAS for leg pain was 6.44 (±2.06), improved to 0,35 (±0.59) postoperatively. Dural injury occurred in 1 patient, treated with dural patch. Improved neurological function was reported in 41/44 Patients (neurological improvement rate of 93%) at the final follow up. There was a significant improvement in the mean ODI values, from 50.19 ± 4.92 preoperatively to 10.14 ± 2.22 postoperatively (P < 0.001). Sixty four out of 66 patients (96%) showed an excellent or good functional outcome according to Macnab´s criteria. No recurrent herniations were observed.

CONCLUSION

The translaminar approach is a viable minimal invasive technique for cranially migrated LDH. The preservation of the flavum ligament is one of the main advantages of this technique. It is an effective, safe and reproducible minimally invasive surgical alternative in treatment of cranially migrated LDHs.

Minimally Invasive Contralateral Over-the-Top Approach for Lumbar Calcified Foraminal Lesions: A Technical Note

BACKGROUND

Various surgical techniques have been described to address intraforaminal/extraforaminal lumbar lesions. They vary from the classic posterior open approaches to minimally invasive techniques with tubular retractors and even endoscopy. These lesions have been approached from either an ipsilateral or a contralateral approach. Only a few reports have described a contralateral minimally invasive tubular approach to address these lesions. However, none of them have been able to address calcified pathologies.

METHOD

We used a contralateral tubular approach to remove the calcified disc herniations in 2 patients presenting with radiculopathy secondary to a calcified intraforaminal L5-S1 disc herniation.

RESULTS

Early clinical and radiological outcomes were positive. No perioperative complications occurred.

CONCLUSIONS

To our knowledge, this is the first report of the expanded use of fixed tubular retractors to address calcified lumbar intraforaminal disc herniations. This approach allows a satisfactory access and view of the contralateral foramen and offending lesion. It permits a wide decompression while preserving the facet joint and thus prevents iatrogenic instability. It can also avoid the iliac crest, which does not allow an ipsilateral extraforaminal approach at the L5-S1 level. This approach is a safe and effective way to treat this specific pathology.

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.

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

BACKGROUND

Several disc disease nomenclatures and approaches for LDH exist. The traditional midline bone-destructive procedures together with approaches requiring extreme muscular retraction are being replaced by muscle sparing, targeted, stability-preserving surgical routes. The increasing speculation on LDHs and the innovative corridors described to treat them have lead to an extensive production of papers frequently treating the same topic but adopting different terminologies and reporting contradictory results.

METHODS

The review of such literature somehow confounding gave us the chance to regroup by surgical corridors the vast amount of approaches for LDH differently renamed over time. Likewise, LDHs were simplified in intra-foraminal (ILDH), extra-foraminal (ELDH), and intra-/extra-foraminal (IELDH) in relation to precise anatomical boundaries and extent of bulging disc.

RESULTS

Through the analysis of the papers, it was possible to identify ideal surgical corridors for ILDHs, ELDHs, and IELDHs, distinguishing for each approach the exposure provided and the technical advantages/disadvantages in terms of muscle trauma, biomechanical stability, and nerve root preservation. A significant disproportion was noted between studies discussing traditional midline approaches or variants of the posterolateral route and those investigating pros and cons of simple or combined alternative corridors. Although rarely discussed, these latter represent valuable strategies particularly for the challenging IELDHs, thanks to the optimal compromise between herniation exposure and bone-muscle preservation.

CONCLUSIONS

The integration of adequate mastery of traditional approaches together with a greater confidence through unfamiliar surgical corridors can improve the development of combined mini-invasive procedures, which seem promising for future targeted LDH excisions.