Lumbar spinal stenosis is a condition that can cause pain, sensory disturbances, and motor deficits due to the compression of neural structures in the lumbar spine. While conservative treatments such as physical therapy and pain management can help some patients, others with persistent neurological deficits may require surgical intervention. Traditional surgical approaches, including open laminectomy, have proven effective but carry risks such as extensive muscle damage, considerable blood loss, postoperative spinal instability, and prolonged recovery times.

This study evaluates a minimally invasive surgical approach called unilateral laminotomy with bilateral lumbar decompression (ULBLD) using endoscopic uniportal technique as an alternative to traditional methods for patients with lumbar spinal stenosis. The main objective is to assess changes in neurological deficits and disability in patients with lumbar spinal stenosis following this procedure. The study will also document hospitalization duration, surgical time, blood loss, and the incidence of postoperative complications.

This multicenter, prospective case series will recruit 78 patients from three medical centers in Mexico. Participants must have symptomatic lumbar spinal stenosis that persists despite at least three months of conservative treatment. Eligible patients will undergo ULBLD using endoscopic uniportal technique, a method that allows precise nerve decompression through a small incision, minimizing damage to surrounding tissues. Standardized clinical assessment tools, including the Japanese Orthopaedic Association (JOA) scale for lumbar disease, Oswestry Disability Index (ODI), and Visual Analog Scale (VAS) for pain, will be used to evaluate outcomes at multiple time points over 12 months.

By comparing patients' preoperative and postoperative evaluations, the study aims to determine whether ULBLD using endoscopic uniportal technique effectively improves neurological function and reduces disability while maintaining a favorable safety profile. Findings from this study could lead to a more precise understanding of the impact of ULBLD on disability, pain, and health-related quality of life for patients with lumbar spinal stenosis.

Lumbar spinal stenosis is a common degenerative condition characterized by narrowing of the lumbar spinal canal, resulting in compression of nerve roots and, in some cases, the spinal cord. This narrowing can be caused by degenerative changes such as hypertrophy of the ligamentum flavum, formation of osteophytes, intervertebral disc protrusion, and thickening of the facet joints. Although its prevalence increases with age, it can affect people of different age groups. Clinically, patients present symptoms such as lumbar pain, neurogenic claudication, paresthesias, and weakness in the lower extremities, which significantly decrease their quality of life. These symptoms limit the ability to perform daily activities and reduce functional independence, affecting the general well-being of individuals.

This study investigates the use of ULBLD using endoscopic uniportal technique, a minimally invasive surgical approach that offers targeted decompression through a single small incision while minimizing tissue disruption. The primary objective of the study is to evaluate changes in neurological deficits and disability in patients with lumbar spinal stenosis following this procedure. Secondary objectives include assessing the duration of hospitalization, surgical time, blood loss, and the incidence of postoperative complications.

This multicenter, prospective case series will recruit 78 patients diagnosed with lumbar spinal stenosis at three medical institutions in Mexico. The study will be conducted over a period of 24 months, with an initial 12-month patient recruitment phase, followed by postoperative follow-up assessments at predetermined time intervals up to one year. Participants will undergo ULBLD using endoscopic uniportal technique, a method designed to preserve spinal mobility while reducing compression on the nerve roots. The procedure will be performed under general anesthesia with continuous neurophysiological monitoring, including somatosensory evoked potentials, motor evoked potentials, and continuous electromyography. Using a working-channel endoscope, surgeons will perform laminotomies to remove compressive elements such as osteophytes, hypertrophic ligaments, or herniated disc material. The technique is aimed at achieving decompression with minimal disruption to the surrounding soft tissues.

Patients must meet specific inclusion criteria, including an age range of 18 to 75 years, confirmed diagnosis of lumbar spinal stenosis (Lee classification grade I-III), and the presence of neurological symptoms unresponsive to at least three months of conservative management. Exclusion criteria include prior lumbar surgery at the affected level, active infections, systemic inflammatory diseases, vertebral instability, congenital spinal malformations, and contraindications for general anesthesia.

Patient outcomes will be systematically evaluated using validated clinical assessment tools, including:

• Japanese Orthopaedic Association (JOA) Scale for lumbar disease to assess neurological function and functional status.
• Oswestry Disability Index (ODI) to measure the impact of lumbar pain on daily activities.
• Visual Analog Scale (VAS) for pain to quantify lumbar and lower limb pain intensity.
• EQ-5D-5L health-related quality of life questionnaire to evaluate overall well-being.
• Modified MacNab Criteria to determine patient satisfaction with surgical outcomes.

Descriptive statistical methods will be used to analyze demographic and clinical characteristics of the study population. Changes in primary and secondary outcomes will be evaluated using paired ttests for continuous variables and Chi-square tests for categorical variables. The impact of the procedure on neurological function and pain relief will be assessed through longitudinal comparisons between baseline and follow-up assessments at 1, 3, 6, and 12 months postoperatively. The incidence of complications will be categorized using the Clavien-Dindo classification, and the Comprehensive Complication Index will be used to quantify cumulative morbidity.

This study complies with the Declaration of Helsinki, the International Council for Harmonisation Good Clinical Practice (ICH-GCP) guidelines, and national regulatory requirements. All participants will provide written informed consent before enrollment, and patient confidentiality will be maintained through data pseudonymization. The study has been approved by the Ethics Committees of the participating institutions.

The expected impact of this study is to generate clinical evidence supporting ULBLD using endoscopic uniportal technique as a safe and effective alternative to traditional surgical approaches for lumbar spinal stenosis.

Inclusion Criteria:

• Provision of informed consent to participate in the study.
• Age ≥18 years and <75 years.
• Patients with lumbar spinal stenosis grade I-III according to the Lee scale.
• Radicular or myelopathic symptoms.
• Having undergone complete conservative management, including physical therapy and analgesia, for at least 3 months.
• Patients who have opted for ULBLD using endoscopic uniportal technique for lumbar spinal stenosis.

Exclusion Criteria:

• Inability to read or write.
• Prior lumbar surgeries at the levels to be treated.
• Infectious symptoms or concomitant rheumatologic diseases.
• Criteria of lumbar vertebral instability.
• Congenital spinal malformations.
• Disc herniation at the same lumbar level to be operated on.
• Medullary hyperintensity on T2-weighted magnetic resonance imaging in the levels to be treated.

Patients with lumbar spinal stenosis who continue to experience symptoms despite receiving complete conservative management for at least 3 months and who have chosen to undergo ULBLD using endoscopic uniportal technique will be recruited consecutively. Recruitment will take place at the following healthcare centers:

• Centro Médico Zambrano-Hellion, TecSalud (San Pedro Garza García, N.L.) and Clínica Cuauhtémoc y Famosa (Monterrey, N.L.). Patients will be recruited by Dr. Mario Benvenutti Regato, a neurosurgery specialist with over 7 years of experience performing endoscopic spine surgery.
• Centro Médico Nacional Siglo XXI (Mexico City)Patients will be recruited by Dr. Félix Domínguez Cortinas, a neurosurgery specialist with over 10 years of experience performing endoscopic spine surgery.
• Hospital Ángeles Tijuana (Tijuana, B.C.)Patients will be recruited by Dr. Alfonso García Chávez, a specialist in traumatology and orthopedics with over 10 years of experience