Cathelin is best remembered for helping to establish caudal (sacral) epidural injection at the dawn of regional anaesthesia. In 1901 he described a “ new spinal route ” via puncture of the sacral canal, supporting correct epidural placement with animal experiments (including dye spread in the epidural space).
He extended the technique to clinical practice and defined Cathelin’s method of caudal epidural anaesthesia. Closely associated with the Paris urological tradition of Félix Guyon (1831–1920), Cathelin explored epidural injections for operative analgesia and pelvic and urinary tract indications.
He consolidated his approach in his 1903 monograph on sacral epidural injections and their applications in urinary disease. Cathelin was also an innovator in urological instrumentation.
In 1902 he introduced a urine-divider (diviseur vésical) to facilitate split urine collection in suspected unilateral renal disease, and in 1905 he developed a cystoscope à air , promoting air cystoscopy as a practical method for direct vision of bladder pathology. He also devised more than 20 further urological instruments .
In 1901 he described a novel spinal route via puncture of the sacral canal, and he supported correct epidural placement through animal experiments that demonstrated dye dispersion within the epidural space.
He extended this technique to human practice and defined Cathelin’s method of caudal epidural anesthesia.
His work is closely tied to the Paris urological tradition associated with Félix Guyon.
In 1902 he introduced a urine-divider (diviseur vésical) to facilitate split urine collection in suspected unilateral renal disease.
In 1905 he developed a cystoscope à air, promoting air cystoscopy as a practical method for direct visualization of bladder pathology.
He contributed more than 20 additional urological instruments as part of his innovations.
Necropsy revealed blackened epidural tissues extending up to the cervical region, intended to confirm correct epidural placement and distinguish the approach from intrathecal injection.
He explicitly stated that he and Jean-Athanase Sicard had worked “simultaneously and independently,” thereby setting aside priority disputes.
This framing reflects the dual aims of analgesia for operative procedures and nonoperative pain relief in pelvic disease contexts.
He argued for safety advantages, including a presumed reduced risk of spinal cord injury, noting that the anesthetic effect would primarily target nerve roots rather than the spinal cord, and that there would be potentially less direct cranial exposure to CSF compared with subarachnoid injection.
He outlined a two-step technical maneuver: pierce the posterior ligaments at an angle, then drop the hub and advance straight within the canal.
This publication framed an integrated understanding of sacral epidural injections and their applications in urinary tract diseases, emphasizing the technique’s indications, mechanism, and method.
It was introduced transurethrally, featuring a metal loop that opened at the tip to bifurcate the bladder into two compartments with a membrane, enabling separate collection from each side.
The device achieved enough notoriety to be lampooned in contemporary caricature as “diviser pour régner.”
Cathelin described the technique as requiring an endoscope inserted with a mandrin, with the bladder examined through an ocular obturator, air introduced via syringe, and urine evacuated through a funnel.
He argued that air cystoscopy permitted upright visualization of objects, avoiding inverted images and magnification effects common to water-based cystoscopy.
He asserted a superiority claim for air-based visualization based on perceived clarity gained in limited time relative to water-based methods.
The narrative also situates Cathelin within the broader European urological milieu, notably the Félix Guyon lineage in Paris.
The available material does not resolve this discrepancy.
It also does not extend to contemporary replication, long-term safety profiles, or standardized practice guidelines.
Cathelin’s integrated presentation—covering anatomy, experimental validation, clinical deployment, and instrument development—illustrates a comprehensive approach to enabling new interventional modalities.