Study designs of evaluations included in the review
Studies of any design were eligible for inclusion in the review.
Specific interventions included in the review
Studies evaluating HVLASM were eligible for inclusion. HVLASM was defined as:
a manual procedure involving the application of a high-velocity, low-amplitude thrust to a given functional spinal unit, causing grade V joint motion into the paraphysiological space and typically resulting in an audible cavitation;
a procedure not administered under any form of anaesthesia; and
adjunctive therapies did not include spinal injections or acupuncture. HVLASM did not have to be the sole intervention evaluated. The included studies evaluated HVLASM with and without physiotherapy, flexion, distraction, McKenzie prone press-ups and bed rest. Where reported, the number of treatment sessions ranged from 1 to 56 over a period of 2 weeks to 10 months; about half of the included studies did not report the treatment frequency. The two studies with control groups compared HVLASM with chemonucleolysis or compared physiotherapy, flexion/distraction with and without HVLASM.
Participants included in the review
Studies including participants with SLDD were eligible for inclusion. Pathology and symptoms of SLDD had to be clearly defined; pathology had to be herniated disk with or without nerve root displacement, or internal disk disruption as demonstrated on magnetic resonance imaging, computed tomography, myelography, epidurography and/or discography. The majority of the included studies evaluated HVLASM in patients with herniated disk.
Outcomes assessed in the review
Studies measuring patient-based outcomes or intermediate outcomes were eligible for inclusion in the review. Patient-based outcomes included pain intensity scales, patient report of pain status and disability (e.g. Oswestry, Roland Morris scales), whilst intermediate outcomes included measures of anatomic or physiologic parameters (via imaging, electrodiagnostic studies, etc.).
How were decisions on the relevance of primary studies made?
The authors did not state how the papers were selected for the review, or how many reviewers performed the selection.