Percutaneous full endoscopic foraminotomy for treatment of cervical spinal nerve compression in horses using a uniportal approach: Feasibility study.

BACKGROUND: Cervical spinal nerve insult can be a sequel of osteoarthropathy in horses due to enlargement of the articular processes (AP). OBJECTIVES: To describe the percutaneous endoscopic cervical foraminotomy procedure in horses. STUDY DESIGN: Ex vivo experimental study and clinical case report. METHODS: The technique was performed in three equine cadavers and in two clinical cases with history of forelimb lameness located in the caudal cervical region. Briefly, the horse was positioned in lateral recumbency, with the affected AP joint uppermost. Under fluoroscopic guidance, the endoscopic instruments (Ø 6.9 mm, length 207 mm, 25° angle of vision) were positioned at the dorsal bony margin of the intervertebral foramen (IVF). The bone was freed from soft tissues and removed using diamond various burrs, hence widening the IVF. The bone drilling was continued until the medial cortical surface of the caudal AP was removed. Thereafter, the endoscope was removed and the skin portal was closed. RESULTS: The average of operation time in clinical cases was 98 ± 24 min. The horses recovered smoothly from the operation. At 12-month follow-up, the clinical signs had resolved completely without recurrence. MAIN LIMITATION: Small number of clinical cases and absence of post-mortem examination or histopathology performed in the cadaver study to assess possible iatrogenic injuries. CONCLUSION: Cervical spinal nerve decompression via minimal invasive foraminotomy is feasible in horses. More research is required before this procedure can be recommended in clinical cases.

The effects of foraminotomy and intervertebral distraction on the volume of the lumbosacral intervertebral neurovascular foramen: An ex vivo study.

Degenerative lumbosacral stenosis in dogs frequently involves L7-S1 foraminal stenosis and L7 nerve root compression. Surgical techniques to decompress the L7 nerve root include foraminotomy and intervertebral distraction. The objective of this study was to compare the effect of foraminotomy and intervertebral distraction on the total, cranial, and caudal compartmental volumes of the L7-S1 intervertebral neurovascular foramen (NF). CT images were obtained from eight canine lumbosacral (L5-CD1) specimens in the following sequential conditions: native spine (1), after dorsal laminectomy and partial discectomy of L7-S1 (2), after L7-S1 foraminotomy (3), after distraction with an interbody cage between L7 and S1 (4), after cage distraction stabilized with pedicle screw-rod fixation in neutral (5) and flexed position (6). The volume of the complete NF and its cranial and caudal subcompartments were calculated using the CT images and statistically compared between conditions. P < 0.05 was considered statistically significant. The volume of the complete NF was significantly increased after foraminotomy (mean ± standard deviation (146.8 ± 26.5%, P < 0.01) and after distraction (Condition 4, 121.0 ± 19.1%; Condition 5, 116.6 ± 29.3 %; Condition 6, 119.0 ± 21.8 %; P = 0.01) with no difference between the distraction conditions. Foraminotomy induced a significantly larger increase in total NF volume compared to distraction. Foraminotomy, but not distraction, induced a significant increase in volume of the cranial subcompartment (158.2 ± 33.2 %; P < 0.01). Foraminotomy is more effective in increasing the foraminal volume and especially the cranial subcompartment, which is where the L7 nerve root traverses the NF. Hence, foraminotomy may be more effective in decompressing the L7 nerve root.

Long-term outcome following lateral foraminotomy as treatment for canine degenerative lumbosacral stenosis.

Lateral foraminotomy has been described as an effective surgical treatment for foraminal stenosis in the treatment of degenerative lumbosacral stenosis (DLSS) in dogs. Clinical records were reviewed from 45 dogs which had undergone lateral foraminotomy at the lumbosacral junction either alone or in combination with decompressive midline dorsal laminectomy. Short-term outcome at six weeks was assessed by the surgeon to be good (11.1 per cent) or excellent (88.9 per cent) in all 45 cases. Long-term outcome beyond six months for lumbosacral syndrome was assessed by the owner as excellent in all 34 cases for which follow-up was available despite recurrence in five cases. Recurrence of clinical signs was not related to re-establishment of foraminal compression at the surgical site when assessed on repeat MRI and was managed by either contralateral foraminotomy in one case or conservative management with excellent response. This study confirms lateral foraminotomy as an effective procedure in the management of DLSS-affected dogs suffering from foraminal stenosis and demonstrates that initial good short-term results are maintained long term despite some treatable recurrences. Lateral foraminotomy is an effective procedure when used appropriately in DLSS with foraminal stenosis either alone or in combination with midline dorsal laminectomy.

Medium-Term Outcome and CT Assessment of Lateral Foraminotomy at the Lumbosacral Junction in Dogs with Degenerative Lumbosacral Stenosis.

OBJECTIVE: This article aims to report the medium-term clinical outcome and assess persistence of enlargement of the lumbosacral lateral intervertebral neurovascular foramen using computed tomography (CT) volumetric analysis in dogs following lateral foraminotomy. MATERIALS: Six dogs that underwent lumbosacral lateral foraminotomy on one or both sides were evaluated with CT prior to, immediately postoperatively (n = 2) and at 12 to 44 months of follow-up. Five out of six dogs had successful clinical outcomes with alleviation of pain and increased levels of activity, according to subjective assessment. Immediate postoperative CT volumetric analysis of the lateral intervertebral neurovascular foramina in two dogs indicated a 650 to 800% increase in volume in extension achieved by foraminotomy (four foramens). At subsequent follow-up, bone regrowth had occurred with reduction in foraminal volume, though in both dogs foraminal volume remained higher than preoperative values. Follow-up CT at a median of 24 months postoperatively indicated a mean 335% increase in volume of the lumbosacral lateral intervertebral neurovascular foramina in extension compared with the preoperative foraminal volume. The follow-up volume was substantially greater than the presurgical volume in four out of six dogs. CLINICAL SIGNIFICANCE: In this limited case series, lateral foraminotomy achieved persistent enlargement of the lumbosacral lateral intervertebral neurovascular foramen in the medium term, but osseous regrowth at the site was demonstrated which may limit the effectiveness of lateral foraminotomy in the longer term. One of two working dogs had recurrent clinical signs that necessitated further surgery.