17.5. Further Follow-up and Outcome Assessment
@ProfFishchenkoAssessment of the outcome of endoscopic surgery does not end at discharge. It is important to follow changes in the patient's symptoms, neurological status, and daily activity, and whether the improvement achieved is sustained.
The organization of early recovery, analgesia, mobilization, and nutrition is discussed in the ERAS chapter. This subsection focuses on subsequent clinical follow-up and assessment of the procedural outcome.
1. Timing of routine assessment in our practice
We perform routine assessment of the patient's condition:
• after lumbar discectomy for disc herniation—at 4 weeks;
• after decompression for lumbar stenosis—at 8 weeks;
• after instrumented lumbar procedures, including BELIF/UBE-LIF—at 8 weeks;
• after cervical procedures—at 3 weeks.
We determine the need for and timing of subsequent examinations according to the type of surgery, baseline neurological deficit, and course of recovery. The first routine review does not always reflect the final outcome. In contemporary BESS/UBE studies, functional outcomes are assessed repeatedly over subsequent months, including at one year after the procedure. Park et al., 2026.
2. What we assess at follow-up
We compare the patient's condition both with the previous examination and with the preoperative presentation and the aim of the procedure.
Pain. We separately assess pain in the lower back and leg and, after cervical surgery, in the neck and arm. We specify its location, intensity, relationship to activity, and the need for analgesic medication.
Neurological status. We test strength and sensation in the relevant areas, comparing them with the baseline deficit. If gait, balance, or hand function is impaired, we follow its evolution. Pain reduction does not by itself replace assessment of motor function.
Functional ability. We establish what the patient can actually do: how far and for how long they can walk, whether they need support, how independent they are in daily life, and which activities remain limited. After decompression for stenosis, the change in walking tolerance is particularly important.
The patient's own assessment. We establish whether the patient perceives improvement and whether the goals for which surgery was performed have been achieved. We record return to work in the context of the type of work, rather than simply as a “yes” or “no” answer.
This multidimensional approach corresponds to the principles of standardized outcome assessment for treatment of degenerative lumbar spine conditions. Clement et al., 2015.
3. Standardized measures and their interpretation
For quantitative assessment of functional limitations, it is appropriate to use:
• ODI — Oswestry Disability Index for lumbar spine conditions;
• NDI — Neck Disability Index for cervical spine conditions.
For subsequent comparison, the score should preferably be recorded before surgery. Clement et al., 2015; Vernon and Mior, 1991.
We assess both the numerical change and its significance for the individual patient. Less pain without recovery of walking ability or with persistent marked weakness does not fully describe the outcome.
We do not use a single numerical threshold as a universal boundary between a “successful” and an “unsuccessful” operation. Thresholds for a minimal clinically important change depend on the measure and condition, as demonstrated, among other studies, by an analysis of the CSORN registry. Power et al., 2023.
4. Follow-up after BELIF/UBE-LIF
After an instrumented procedure, we distinguish clinical recovery from formation of spinal fusion. Pain reduction and improved activity are not independent evidence of bony fusion.
Routine assessment at 8 weeks primarily characterizes the patient's clinical condition at that stage. In Pao's study of biportal endoscopic interbody fusion, the degree of fusion was assessed by CT one year after surgery. Pao, 2023.
We formulate the question for repeat imaging according to the clinical situation: what needs to be clarified, and whether the result will affect further management. The principles of postoperative MRI and CT are provided in §17.4.
5. When we revise the follow-up plan
We distinguish three situations:
• symptoms are gradually diminishing but have not yet resolved;
• the expected improvement has not occurred;
• symptoms have returned after improvement or new symptoms have developed.
These situations require different assessments. A return of pain alone does not confirm recurrent disc herniation, and persistent numbness does not by itself prove inadequate decompression. We clarify the course, repeat clinical and neurological examinations, and determine the need for additional evaluation.
A new or increasing neurological deficit requires urgent assessment regardless of the scheduled review date. Concerning changes are discussed in more detail in §17.2.
The follow-up record specifies the time since surgery, evolution of symptoms, neurological and functional measures, the need for additional studies, and the subsequent plan. We separately document complications, readmissions, and repeat procedures.
Practical principle: we assess the surgical outcome over time through the patient's condition, functional recovery, and durability of improvement, rather than pain intensity or the appearance of a follow-up image alone.
References
1. Clement R.C., Welander A., Stowell C., et al. A proposed set of metrics for standardized outcome reporting in the management of low back pain. Acta Orthopaedica. 2015;86(5):523–533. DOI: 10.3109/17453674.2015.1036696.
2. Park H.J., Kim J.S., Park S.M., et al. Is Biportal Endoscopic Laminectomy Equivalent to Microscopic Laminectomy in Patients With Lumbar Spinal Stenosis? A Multicenter, Assessor-blind, Randomized Clinical Trial. Clinical Orthopaedics and Related Research. 2026;484(2):341–353. DOI: 10.1097/CORR.0000000000003695.
3. Vernon H., Mior S. The Neck Disability Index: a study of reliability and validity. Journal of Manipulative and Physiological Therapeutics. 1991;14(7):409–415. PubMed.
4. Power J.D., Perruccio A.V., Canizares M., et al. Determining minimal clinically important difference estimates following surgery for degenerative conditions of the lumbar spine: analysis of the Canadian Spine Outcomes and Research Network (CSORN) registry. The Spine Journal. 2023;23(9):1323–1333. DOI: 10.1016/j.spinee.2023.05.001.
5. Pao J.L. Biportal Endoscopic Transforaminal Lumbar Interbody Fusion Using Double Cages: Surgical Techniques and Treatment Outcomes. Neurospine. 2023;20(1):80–91. DOI: 10.14245/ns.2346036.018.
Previous subsection: 17.4. Postoperative Imaging: Correlation with the Clinical Presentation
Chapter 17. Postoperative Period